many thanks to all that replied to this post and a big thanks to WILLz and Zeus that ahad a spot on diagnosis of the problem....did what you said and was up and running in 10 minutes.
once again many thanks to all replies
have just installed a new mobo and processor to pc
Asus av8 mobo
athlon64 3700+
switches on ok and first screen recognises chip but then stops and says
The processor installed in your system are of an unknown revision..please contact your bios vendor for appropriate updates.
Fatal...