XP "Not Registered" error, but no changes to hardware

[BennyLava]

I am currently running a Windows XP home PC (SP3), this has worked fine for the past few years but all of a sudden, I am getting an error message advising that Windows XP is no longer registered due to a significant hardware change.

The thing is that I have not changed any hardware whatsoever since I have had the machine.

One other thing to note is that since I started getting this error message, I am no longer able to access the internet on this machine.

Has anyone out there come across this issue before? To be quite honest I am not sure where to begin in diagnosing/resolving the issue, so any help or advice on this problem would be greatly appreaciated!

Thanks in Advance for any help offered!

Benny

 

[JasonWinTeam]

Interesting... This could be a virus. Do you have antivirus software installed? And what happens when you try to get on the Internet?

 

[BennyLava]

AV Software

I have AVG free installed and whilst I appreciate that this isn't the best AV software out there, it has done for me in the past.

AVG has not flagged anything up automatically, and neither did a full scan - though I can't rule out the possibility that the machine is infected

The activation request looks fairly legit, though I know that some malware can look very convincing!

I've searched on Google for answers on this issue, and whilst lots of people have reported the same problem, there seems to be no definite cause/solution - so I'm feeling a bit stumped!

EDIT:

When trying to get online, I simply get the "this page cannot be displayed" message, my laptop can access the internet fine, so I can rule out it being an issue with my router/connection