My really good PC cant run games i was able to run before

[pfb]

I have a computer that was really fast and still has more than haft of its memory and i cant run any new games like shogun 2 company of heroes are so laggy now and the were really fast. what is wrong

 

[Brett928S2]

specs ?

 

[wrathofdragon]

specs ?

Also: did you recently update drivers/software, or install new hardware/ remove old hardware?
Do you have an antivirus?

 

[solidsteel]

Might help to run a thorough CCleaner and restart. Defrag Steam games, perhaps reinstall Steam games, and if all else fails try a complete Windows re-install.