Post edited: apologies typed system32.dll instead of shell32.dll.
Apparently I have a MBR virus (I use AVG it reports that MBR change when I run the virus checker). Also, this morning when I started my PC it reported a MBR error and also a change in SHELL32.DLL & KERNEL32.DLL. Unfortunately (& being stupid) I managed to click 'Change Confirm' rather then 'Ignore' on the AVG screen for both of these DLLs. They have now changed. Is there any way of going back? The bad news is the System Restore doesn't work.
Now AVG says MBR changed but I can't seem to do anything with it.
So far, the PC has not crashed or has not misbehaved itself so far. But I am not sure if there is a virus or not. I would dearly like to go back to my previous SHELL32.DLL & KERNEL32.dll files.
Any ideas/fixes more than welcome.