Hi Alan - I can't see a response regarding my post a week ago and I'm still having no joy with this printer. Please see below:

I opened 5 of the WER files and they seemed pretty much identical. ie they all had Driver Package Hash mentioned. I have pasted one below:

Version=1
EventType=PnPDriverInstallError
EventTime=128686308933330826
Consent=1
UploadTime=128686308933330826
Response.BucketId=264434259
Response.BucketTable=5
Response.type=4
Sig[0].Name=Architecture
Sig[0].Value=x86
Sig[1].Name=Win32 error
Sig[1].Value=E0000246
Sig[2].Name=Inf name
Sig[2].Value=lxdxprc.inf
Sig[3].Name=Driver Package hash
Sig[3].Value=2f82aff0f2229b2000559007afa20aaff1b26ad9
Sig[4].Name=DDInstall section name
Sig[4].Value=INST_DRVR_NT_5_1
DynamicSig[1].Name=OS Version
DynamicSig[1].Value=6.0.6000.2.0.0.768.2
DynamicSig[2].Name=Locale ID
DynamicSig[2].Value=2057
State[0].Key=Transport.DoneStage1
State[0].Value=1
FriendlyEventName=Could not install driver software for device
ConsentKey=PnPDriverInstallError
AppName=Driver software installation
AppPath=C:\Windows\System32\svchost.exe
ReportDescription=Windows encountered a problem while installing device drivers for your Lexmark 3600-4600 Series

I then installed the debugger files as you suggest but I'm afraid after that I got lost with your instructions. Please could you clarify?

No-one else seems to have any suggestions for me so am very grateful for your help.

Many thanks