If that .reg file gets blocked then copy the folowing text into notepad,
save as xxxx.reg and then double click:
Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\.wmv]
"PerceivedType"="video"

[HKEY_CLASSES_ROOT\.wmv\shellex]

[HKEY_CLASSES_ROOT\.wmv\shellex\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}]
@="{c5a40261-cd64-4ccf-84cb-c394da41d590}"

[HKEY_CLASSES_ROOT\WMVFile]
@="Windows Media Audio/Video file"
"EditFlags"=hex:00,00,01,00
"FriendlyTypeName"=hex(2):40,00,25,00,53,00,79,00, 73,00,74,00,65,00,6d,00,52,\
00,6f,00,6f,00,74,00,25,00,5c,00,73,00,79,00,73,00 ,74,00,65,00,6d,00,33,00,\
32,00,5c,00,75,00,6e,00,72,00,65,00,67,00,6d,00,70 ,00,32,00,2e,00,65,00,78,\
00,65,00,2c,00,2d,00,39,00,39,00,31,00,34,00,00,00
"PreferExecuteOnMismatch"=dword:00000001

[HKEY_CLASSES_ROOT\WMVFile\DefaultIcon]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00 ,52,00,6f,00,6f,00,74,00,25,\
00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00 ,32,00,5c,00,77,00,6d,00,\
70,00,6c,00,6f,00,63,00,2e,00,64,00,6c,00,6c,00,2c ,00,2d,00,37,00,33,00,36,\
00,00,00

[HKEY_CLASSES_ROOT\WMVFile\shell]
@="Play"

[HKEY_CLASSES_ROOT\WMVFile\shell\open]
"LegacyDisable"=""

[HKEY_CLASSES_ROOT\WMVFile\shell\open\command]
@=hex(2):22,00,25,00,50,00,72,00,6f,00,67,00,72,00 ,61,00,6d,00,46,00,69,00,6c,\
00,65,00,73,00,25,00,5c,00,57,00,69,00,6e,00,64,00 ,6f,00,77,00,73,00,20,00,\
4d,00,65,00,64,00,69,00,61,00,20,00,50,00,6c,00,61 ,00,79,00,65,00,72,00,5c,\
00,77,00,6d,00,70,00,6c,00,61,00,79,00,65,00,72,00 ,2e,00,65,00,78,00,65,00,\
22,00,20,00,2f,00,70,00,72,00,65,00,66,00,65,00,74 ,00,63,00,68,00,3a,00,37,\
00,20,00,2f,00,4f,00,70,00,65,00,6e,00,20,00,22,00 ,25,00,4c,00,22,00,00,00

[HKEY_CLASSES_ROOT\WMVFile\shell\open\DropTarget]
"CLSID"="{CE3FB1D1-02AE-4a5f-A6E9-D9F1B4073E6C}"

[HKEY_CLASSES_ROOT\WMVFile\shell\play]
@="&Play"
"MUIVerb"=hex(2):40,00,25,00,53,00,79,00,73,00,74, 00,65,00,6d,00,52,00,6f,00,\
6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65 ,00,6d,00,33,00,32,00,5c,\
00,75,00,6e,00,72,00,65,00,67,00,6d,00,70,00,32,00 ,2e,00,65,00,78,00,65,00,\
2c,00,2d,00,39,00,39,00,39,00,31,00,00,00
"LegacyDisable"=""

[HKEY_CLASSES_ROOT\WMVFile\shell\play\command]
@=hex(2):22,00,25,00,50,00,72,00,6f,00,67,00,72,00 ,61,00,6d,00,46,00,69,00,6c,\
00,65,00,73,00,25,00,5c,00,57,00,69,00,6e,00,64,00 ,6f,00,77,00,73,00,20,00,\
4d,00,65,00,64,00,69,00,61,00,20,00,50,00,6c,00,61 ,00,79,00,65,00,72,00,5c,\
00,77,00,6d,00,70,00,6c,00,61,00,79,00,65,00,72,00 ,2e,00,65,00,78,00,65,00,\
22,00,20,00,2f,00,70,00,72,00,65,00,66,00,65,00,74 ,00,63,00,68,00,3a,00,37,\
00,20,00,2f,00,50,00,6c,00,61,00,79,00,20,00,22,00 ,25,00,4c,00,22,00,00,00

[HKEY_CLASSES_ROOT\WMVFile\shell\play\DropTarget]
"CLSID"="{CE3FB1D1-02AE-4a5f-A6E9-D9F1B4073E6C}"

[HKEY_CLASSES_ROOT\WMVFile\shellex]

[HKEY_CLASSES_ROOT\WMVFile\shellex\ContextMenuHandl ers]

[HKEY_CLASSES_ROOT\WMVFile\shellex\ContextMenuHandl ers\PlayOnMyTV]
@="{FFB699E0-306A-11d3-8BD1-00104B6F7516}"

[HKEY_CLASSES_ROOT\WMVFile\shellex\ContextMenuHandl ers\WMPAddToPlaylist]
@="{F1B9284F-E9DC-4e68-9D7E-42362A59F0FD}"

[HKEY_CLASSES_ROOT\WMVFile\shellex\ContextMenuHandl ers\WMPPlayAsPlaylist]
@="{CE3FB1D1-02AE-4a5f-A6E9-D9F1B4073E6C}"

[HKEY_CLASSES_ROOT\WMVFile\shellex\{8895b1c6-b41f-4c1c-a562-0d564250836f}]
@="{031EE060-67BC-460d-8847-E4A7C5E45A27}"

[HKEY_CLASSES_ROOT\WMVFile\VideoClipContainer]
@="{5cdcb131-a1a1-4fe9-9a10-80effe042ae0}"

[HKEY_CLASSES_ROOT\.avi]
@="WMP.AVI"
"PerceivedType"="video"
"MP2.Last"="Custom"
"MPlayer2.BAK"="NeroShowTime.Files7.avi"

[HKEY_CLASSES_ROOT\.avi\OpenWithProgIds]
"WMP.AVI"=hex(0):

[HKEY_CLASSES_ROOT\.avi\ShellEx]

[HKEY_CLASSES_ROOT\.avi\ShellEx\{BB2E617C-0920-11D1-9A0B-00C04FC2D6C1}]
@="{c5a40261-cd64-4ccf-84cb-c394da41d590}"

[HKEY_CLASSES_ROOT\.avi\ShellEx\{e357fccd-a995-4576-b01f-234630154e96}]
@="{9DBD2C50-62AD-11D0-B806-00C04FD706EC}"

[HKEY_CLASSES_ROOT\AVIFile]
@="Video Clip"
"EditFlags"=hex:00,00,01,00
"FriendlyTypeName"=hex(2):40,00,25,00,53,00,79,00, 73,00,74,00,65,00,6d,00,52,\
00,6f,00,6f,00,74,00,25,00,5c,00,73,00,79,00,73,00 ,74,00,65,00,6d,00,33,00,\
32,00,5c,00,75,00,6e,00,72,00,65,00,67,00,6d,00,70 ,00,32,00,2e,00,65,00,78,\
00,65,00,2c,00,2d,00,39,00,39,00,30,00,35,00,00,00
"PreferExecuteOnMismatch"=dword:00000001

[HKEY_CLASSES_ROOT\AVIFile\CLSID]
@="{00022602-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Compressors]

[HKEY_CLASSES_ROOT\AVIFile\Compressors\auds]
@="{0002000F-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Compressors\vids]
@="{00020001-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\DefaultIcon]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00 ,52,00,6f,00,6f,00,74,00,25,\
00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00 ,32,00,5c,00,77,00,6d,00,\
70,00,6c,00,6f,00,63,00,2e,00,64,00,6c,00,6c,00,2c ,00,2d,00,37,00,33,00,31,\
00,00,00

[HKEY_CLASSES_ROOT\AVIFile\Extensions]

[HKEY_CLASSES_ROOT\AVIFile\Extensions\AU]
@="{00020003-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Extensions\AVI]
@="{00020000-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Extensions\BMP]
@="{00020006-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Extensions\DIB]
@="{00020006-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Extensions\FLC]
@="{00020007-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Extensions\FLI]
@="{00020007-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Extensions\TGA]
@="{0002000A-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\Extensions\WAV]
@="{00020003-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\RIFFHandlers]

[HKEY_CLASSES_ROOT\AVIFile\RIFFHandlers\AVI]
@="{00020000-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\RIFFHandlers\WAVE]
@="{00020003-0000-0000-C000-000000000046}"

[HKEY_CLASSES_ROOT\AVIFile\shell]
@="Play"

[HKEY_CLASSES_ROOT\AVIFile\shell\open]
"LegacyDisable"=""

[HKEY_CLASSES_ROOT\AVIFile\shell\open\command]
@=hex(2):22,00,25,00,50,00,72,00,6f,00,67,00,72,00 ,61,00,6d,00,46,00,69,00,6c,\
00,65,00,73,00,25,00,5c,00,57,00,69,00,6e,00,64,00 ,6f,00,77,00,73,00,20,00,\
4d,00,65,00,64,00,69,00,61,00,20,00,50,00,6c,00,61 ,00,79,00,65,00,72,00,5c,\
00,77,00,6d,00,70,00,6c,00,61,00,79,00,65,00,72,00 ,2e,00,65,00,78,00,65,00,\
22,00,20,00,2f,00,70,00,72,00,65,00,66,00,65,00,74 ,00,63,00,68,00,3a,00,38,\
00,20,00,2f,00,4f,00,70,00,65,00,6e,00,20,00,22,00 ,25,00,4c,00,22,00,00,00

[HKEY_CLASSES_ROOT\AVIFile\shell\open\DropTarget]
"CLSID"="{CE3FB1D1-02AE-4a5f-A6E9-D9F1B4073E6C}"

[HKEY_CLASSES_ROOT\AVIFile\shell\play]
@="&Play"
"MUIVerb"=hex(2):40,00,25,00,53,00,79,00,73,00,74, 00,65,00,6d,00,52,00,6f,00,\
6f,00,74,00,25,00,5c,00,73,00,79,00,73,00,74,00,65 ,00,6d,00,33,00,32,00,5c,\
00,75,00,6e,00,72,00,65,00,67,00,6d,00,70,00,32,00 ,2e,00,65,00,78,00,65,00,\
2c,00,2d,00,39,00,39,00,39,00,31,00,00,00
"LegacyDisable"=""

[HKEY_CLASSES_ROOT\AVIFile\shell\play\command]
@=hex(2):22,00,25,00,50,00,72,00,6f,00,67,00,72,00 ,61,00,6d,00,46,00,69,00,6c,\
00,65,00,73,00,25,00,5c,00,57,00,69,00,6e,00,64,00 ,6f,00,77,00,73,00,20,00,\
4d,00,65,00,64,00,69,00,61,00,20,00,50,00,6c,00,61 ,00,79,00,65,00,72,00,5c,\
00,77,00,6d,00,70,00,6c,00,61,00,79,00,65,00,72,00 ,2e,00,65,00,78,00,65,00,\
22,00,20,00,2f,00,70,00,72,00,65,00,66,00,65,00,74 ,00,63,00,68,00,3a,00,38,\
00,20,00,2f,00,50,00,6c,00,61,00,79,00,20,00,22,00 ,25,00,4c,00,22,00,00,00

[HKEY_CLASSES_ROOT\AVIFile\shell\play\DropTarget]
"CLSID"="{CE3FB1D1-02AE-4a5f-A6E9-D9F1B4073E6C}"

[HKEY_CLASSES_ROOT\AVIFile\shellex]

[HKEY_CLASSES_ROOT\AVIFile\shellex\ContextMenuHandl ers]

[HKEY_CLASSES_ROOT\AVIFile\shellex\ContextMenuHandl ers\PlayOnMyTV]
@="{FFB699E0-306A-11d3-8BD1-00104B6F7516}"

[HKEY_CLASSES_ROOT\AVIFile\shellex\ContextMenuHandl ers\WMPAddToPlaylist]
@="{F1B9284F-E9DC-4e68-9D7E-42362A59F0FD}"

[HKEY_CLASSES_ROOT\AVIFile\shellex\ContextMenuHandl ers\WMPPlayAsPlaylist]
@="{CE3FB1D1-02AE-4a5f-A6E9-D9F1B4073E6C}"

[HKEY_CLASSES_ROOT\AVIFile\shellex\{8895b1c6-b41f-4c1c-a562-0d564250836f}]
@="{031EE060-67BC-460d-8847-E4A7C5E45A27}"

[HKEY_CLASSES_ROOT\AVIFile\VideoClipContainer]
@="{5cdcb131-a1a1-4fe9-9a10-80effe042ae0}"

[HKEY_CLASSES_ROOT\.mpg]
"PerceivedType"="video"

[HKEY_CLASSES_ROOT\.mpg\shellex]

[HKEY_CLASSES_ROOT\.mpg\shellex\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}]
@="{c5a40261-cd64-4ccf-84cb-c394da41d590}"

[HKEY_CLASSES_ROOT\.mpeg]
"PerceivedType"="video"

[HKEY_CLASSES_ROOT\.mpeg\shellex]

[HKEY_CLASSES_ROOT\.mpeg\shellex\{BB2E617C-0920-11d1-9A0B-00C04FC2D6C1}]
@="{c5a40261-cd64-4ccf-84cb-c394da41d590}"

[HKEY_CLASSES_ROOT\.jpg]
"PerceivedType"="image"

[HKEY_CLASSES_ROOT\.jpeg]
"PerceivedType"="image"

[HKEY_CLASSES_ROOT\.png]
"PerceivedType"="image"

[HKEY_CLASSES_ROOT\.gif]
"PerceivedType"="image"