I have G Skill 1gb pc3200 DDR400 ram stick, and x2 Kingston 512 MB pc3200 ram stick(1gb) and when i put them all in it does not work, it goes to the windows loading screen then freezes....... but when i just put the g skill 1gb it starts up normal. same with the 2 sticks by it self.... how can i prevent it from freezing and booting up normal. the 2 gigs only works in safe mode with all the sticks in.

Please provide us with the make/model of your motherboard

it sounds like your motherboard might not support 2 gigs.

its a Asus P4P800 SE, it supports up to 4 gigs of ram

are the Memory Timings set correctly in the BIOS? that can cause problems like this sometimes.

Yes you are correct, your Motherboard does support 4GB as shown HERE

Although the memory can be installed one module at a time, the best performance comes from using matched pairs of modules.

Each memory slot can hold DDR PC3200,DDR PC2700,DDR PC4000 with a maximum of 1GB per slot.*

I have seen when trying to run CL=2.5 and CL=3 caused issues, have you checked this