EDIT : To remove the instruction to register mshtml.dll after reading DJLizards reply.
Hi Poppadum, Welcome to the forum,
What happens if you go to Start Menu then run and type
Appwiz.cpl
Press Ok, this should open the Add/Remove screen.
Next try re-registering these files
Can you open Notepad (Start Menu > run > type notepad and press OK)
Then copy and paste the contents of the code box into Notepad:
CODE
regsvr32 /s %systemroot%\System32\Appwiz.cpl
regsvr32 /s %systemroot%\System32\Jscript.dll
regsvr32 /s %systemroot%\System32\Msi.dll
regsvr32 /s %systemroot%\System32\Mshtmled.dll
regsvr32 /s %systemroot%\System32\Ole32.dll
regsvr32 /s %systemroot%\System32\Urlmon.dll
regsvr32 /s %systemroot%\System32\Clbcatq.dll
regsvr32 /s %systemroot%\System32\Oleaut32.dll
regsvr32 /s %systemroot%\System32\Mlang.dll
regsvr32 /s %systemroot%\System32\Shell32.dll
regsvr32 /s %systemroot%\System32\Plugin.ocx
regsvr32 /s %systemroot%\System32\Imgutil.dll
regsvr32 /s %systemroot%\System32\Cscui.dll
EXIT
Goto File on the top bar of notepad and choose
Save As, On the
Save As Type change it to
All Files, name it
fix.bat and save it to your desktop
Double click fix.bat, you will just notice cmd screen open then list each file and close, its then finished and registered the files.
Reboot the pc and check Add/Remove again
If that doesnt help there's likely to be some registry corruption so its difficult to know where to start, One option is performing a repair install of Windows but you will need to upgrade the service packs and updates if you use that option. Maybe other members can offer some suggestions if the above doesnt help.