I have a Dell Dimension 5100, and whenever I press the power button, it won't turn on. It all began when I was playing a game, and the screen froze and became distorted with blue streaks before it shut off. At first, I thought there was a problem with over heating, so I got some canned air and I cleaned out the fans, case, and components; especially the graphics card. I plug it all back in, and nothing happens when I press the power button. Even though the mobo has a green light on, showing that there is power flow, the power button is completely unresponsive. I waited over night, and turned it on in the morning, but the moment the Dell splash screen came up, there were green streaks everywhere. I was almost certain it was the graphics card, so I took it out and used the onboard video, and the computer worked fine. However, I'm a PC gamer and a Vista user at that, so it's incredibly hard to get around without a GPU and a piss-poor Pentium 4 CPU. So, thinking that the card was dead, I replaced it with an 8600GTS (not the best option since it's power hungry, but it was the only retail card available). Dell being Dell, they only have two molex connectors, so I disconnected them from the DVD drives to use as the 6-pin supplementary power source. Nothing. So now it has come down to replacing my power supply, but I've read so many different stories across the internet about whether Dell uses a proprietary PSU or not. Some say they still do, other say they stopped using them anywhere from 2000 to 2002. I also heard that loads of them don't fit inside the case. The other option is the build a new PC by getting a new mobo, PSU, and case, and stuffing all the old components in there. However, my Dell has 1.5GBs of DDR2 400 RAM, and if I get a new mobo, it will most likely have a DDR2 800 standard. Is it still possible to use this RAM, or will I need to buy some? Just as an update, there's a green light and all, but now the PC won't start up regardless of what's in there. Is the mobo busted?