A little while ago I had a spyware/virus scare that now seems to be taken care of, except that I don't understand what AVG is trying to tell me when I run a virus scan.

The summary gives a list of files checked and listed as "OK", except for three files tthat it lists as "Change".

The three files are:
C:\Windows\System32\user32.dll
C:\Windows\System32\shell32.dll
C:\Windows\System32\ntoskrnl.exe

What is AVG trying to tell me when it says "Change" instead of "OK" by these files? At the end of the scan it says no viruses found.

Should I be worried about this? Should I be doing something?

I have refrained from using my backup disk (external USB hard drive) until I know more about it.

tanstaafl.