Hi. I was given a Dell Dimension L933r computer by a friend for my mother to use. We couldn't afford an extra computer so I was going to reformat and install Windows XP Pro. The comp came with Windows ME and had been upgraded to Windows XP Home. My friend tested it and told me it worked fine and could browse the internet. It just needed a wireless network card. I tested the computer and it ran fine like she said, but I saw it had 384 mb of memory and could handle an upgrade to 512. I had an extra 256 mb stick so I attempted to upgrade it and put in a small drive. Once I tried to turn the comp, back on it didn't work at all. It wouldn't turn on and made no noise at all. I read that these computers needed a 8 chip memory and mine was like this. However I put back in the original memory and removed the slave drive and it still wouldn't boot up. All the cables were working properly and were properly plugged in. My power cord and the power plug is working fine. I spoke to a dell rep in tech chat and he said the power supply had likely stopped working and that the motherboard could be bad. I had considered that the power supply could be the problem, but I can someone explain why the comp worked fine and powered up several times with no problems before I upgraded the ram and then didn't after that? Was it really due to the ram upgrade? And if that's the case why didn't the comp work after I undid my tweaks with the ram and hdds? I have an old Dell Optiplex GXP1 and it has a 200 watt hard drive. The tech at dell said the Dimension used a 145 watt drive and the other power supply wouldn't work. I Is this really true? I saw a site that was selling power supplies compatible to this comp and they were 200 watts. Also before I attempted anything I was wondering if even the power supply would work if it fit into the smaller Dimension tower after coming from a larger size Optiplex. All the hard drives work fine that would go in the comp. Also the comp had a lot of dust and I had no compressed air can to get it out. Is it possible that the dust made it stop working since it was opened and I tried to fix it and the dust could have touched something? I've worked on dusty computers before, but none had this problem until now. I wanted help to make sure I know how to best proceed. I'd really like for my mom to have something to use in her room if just to do some Publisher docs and serf the web. I had considered trying to transfer my Optiplex motherboard, but I think it's too large to fit in the Dimension tower. I would appreciate any help you all could give. Sorry for all my questions and everything, but I'm trying to address everything I did and all my problems in this one post to keep from having to answer questions later from you all, which could have been answered in this post.