I salvaged some RAM from my friends computer and put it in the free slot in mine, I thought I had plugged it in all the way but it wasn't, and I tried to boot my computer. The fans run but there is no output on the screen and the front LED was blinking red. and the lights on the keyboard were blinking. I shut it off, removed the new RAM, and turned it back on but it still did the same.
Anyone know what might be wrong?

I'm not really a computer expert or anything.. I thought I knew how to install RAM but obviously not.

**EDIT**
Oh and I have a PC running XP. It's an Altex brand if that makes any difference.

Mixing RAM is not usually a good idea. In general you want identical sticks. But that may not be the problem at the moment.

I'd reseat one old stick in the first slot and see what happens.

If still nothing try booting with no RAM. The computer should beep constantly at this point. Does it?

Also clearing the CMOS might help.

Were you being careful to ground yourself while you were inside the computer?

In addition to what Jephree said, some motherboards are very picky about what ram goes in there. Are you positive that the ram you threw in there was compatible with your motherboard? DDR and DDR2 may look similar, but have different pin counts. It isnt hard to push too hard and break something around your memory slots.