new ram causing problems

i recently purchased ram from crucial.com to upgrade my pavilion 751n PC. it's quite old(2001 i believe), and i desperatley needed a ram upgrade. my friend hooked me up with a 128 MB stick of pc2700 ram until i could buy my own. that stick worked fine with the original 256 MB of pc2100 ram. i recieved my 1GB stick of pc2700 ram from crucial, and pulled the other two out. when i started up my computer, it wouldn't boot up windows until i clicked "revert to last known good config.". then, games/apps would randomly close without warning, and sometimes, the computer would shut off. is this simply a faulty piece of memory, or is it my computer's fault? P.S. i also ran windows memory diagnostic, and the memory failed a test after the 3rd pass.

 

make sure that your computer is actually seeing the new ram in it's entirety. Also, make sure you definitely secured the ram in place, as im sure almost everyone has had that problem before.

 

After you check that, are you getting a windows BSOD? (Blue screen) It could be a bad stick of Ram. It does happen.