We need more information.
1) Make/model of PC.
2) How many sticks of ram does it currently have in it 2/3/4?
Has 4 sticks of ddr2....HP Pavilion Elite m9520f desktop pc. I removed two closest to cpu...and it booted into windows but then shortly after froze up with 'text message screen' indicating it had to shut down pc to protect...or some such mssg. Have NO idea what that means.