Hcl desktop
Allways showing the message that "you may be a victim of softwarecounterfeiting, ask for genuine software".and not able to set wallpape

I had purchased the computer 4 months before from vapi, gujarat .it is intel core2duo, lcd moniter, windows xp.now the message has came that "you me a victim of software counter feiting, this windows did not pass genuine windows validation, ask for genuine windows software".

and not able to set the wall paper.

pls resolve the problem immediately.

thank you

kanthaswami