Problems began arising when I got my new videocard. An ATI Radeon 9550.
Recently, I put in an additional 512mbs of RAM. I believe I seated it wrong because my computer IMMEDIATELY shut off. I reseat the RAM and it appeared that the monitor quit responding. The LED for the power doesn't turn green anymore, but oddly enough the reset button LED comes on and the monitor still won't display anything.
I tried replacing my PSU, that didn't do anything, I took out the new stick of RAM and that didn't help either.
Any help is appreciated. =]