A place to check if your PC can run it is at http://www.yougamers.com/
It's a site by FutureMark (makers of the 3DMark benchmarking program) that will check your PC (CPU, Memory, GPU, etc) to see if your machine meets the minimum, recommended or optimal specs to run the game. It's been pretty spot on for me.
My specs are AMD64 X2 4200+, ATI HD3870 w/512mb GDDR4 RAM, 4 gigs PC3200 RAM, Windows 7 64 Professional, onboard sound card (RealTek) and I'm running Dragon Age at 1280x1024 with just about everything turned on and it run pretty darn well. Not 60+ FPS, but definitely above 40. It does have SOME slowdowns, but during battles, it runs fine.