If you have PCI-Express 2.0 x16, you'll be fine. If you don't, sucks to be you. Usually you can check by looking up your motherboard or just by remembering what it was when you built it (if you did).
http://www.cpuid.com/cpuz.phpDownload this, it gives specs of your hardware.What video card you have now?
NVIDIA GeForce 6150SE nForce 430