Yesterday, I got my new MSI K8T Neo2-F 939 socket mobo with an Athlon 64 3200+ and 1gb of RAM. Hooray. Quickly to the point, when I installed everything, I plugged everything necessary into the ports, and tried booting up the computer. The monitor was black, and remained black, so I was a bit suspicious. I opened my case back up and saw that my video card's fan wasn't on. Something was wrong... I brought my card to my friend's house to see if it were a problem with my card, but it worked on his system, so it made me realize it was a problem with the motherboard. Is there any certain explanation other than "your motherboard is broken" that anyone can think of?

You might want to try reseating it in the slot. Sometimes they need an extra push to get them to seat properly.