Long story short, I'm another one of the dozens of people whose shortcuts and
start menu files have turned into unassociated .lnk files. I've looked at
several other threads and tried the fix that they point to, namely the .reg
fix file. However, whenever I try to merge the file I get an error message
that reads:

Cannot import C:\lnk_vista.reg: Not all data was successfully written to the
registry. Some of the keys are open by the system or other processes.

I've tried closing every program in the task manager that will stay closed
and it still gives the error message. I've tried moving the file from C:\ to
the desktop, tried running regedit and merging the file through that and no
luck. Could it have something to do with the fact that I manually assigned
an association to the .lnk extension through the Default Programs option? If
so then is there any way to dis-associate them so they can be properly
re-associated? Or does anyone know any other way to fix this problem?