Geforce 6800 Problem

[BlackMagic]

Hi all just recently my geforce 6800 has been running most games at 30 or below fps it starts out at a higher fps but drops later on.

I have the latest drivers and have checked for viruses.

I have unistalled the card and reinstalled the card.

I have a p4 3.2 gig chip asus p4p800SE mo bo 1 gig ram 200 gig hd,
and cant think of the reason it has started behaving like this.

And yes it used to perform much better than this.

So any advice would be appreciated.

Thanks in advance.

BM