Did you have a internal PC speaker attached to the motherboard? This would have plugged in to a 4 pin header near where the power button for the computer case plugs in, or sometimes the speaker is built in. If you did have it connected you would have heard a single beep everytime you turned on the computer.
I think it might be the MOBO, it just froze when I was in the bios and I am not always getting a video signal to the monitor.
If the video does not come on you normally would hear beeps from the internal speaker indicating either video card or RAM. If the internal speaker was plugged in but no beeps were heard it would be the motherboard or something plugged into the motherboard.
If no beeps are heard the best thing to do is to remove everything from the motherboard except for power and CPU. Remove RAM, video, SATA/IDE drive cables, add on cards, etc. Then power on the computer. If the internal speaker is functioning you should hear error beeps indicating no RAM or no video, if no beeps are heard then almost always the motherboard is bad. Bad CPU is much less common but can cause the same symptoms.
Because the computer does boot up and then freezes later it may take some time to diagnose in this way.
After it froze with 1 stick of RAM removed, did you trying removing the one it froze with and putting back the one you originally removed?
If you feel it is the RAM you can run memtest
http://www.memtest.orgDoes the motherboard have onboard video?