Hello, thanks for looking! I'm sorry this is going to be a lot to read! I've been having a lot of problems with my system ever since I (stupidly) switched the power on and off quickly. First, I had to replace the power supply for my monitor only to find my system not booting. No lights on the case, not anything. I got another power supply, hooked into my system and nothing changed. The only thing I could imagine was the mother board not booting. I replaced the battery. Nothing. I left it out for 24 hrs to clear the bios. Nothing. Finally I ordered a Jetway 845PEMAX motherboard off of eBay. I have a P4 socket 478 and had a hard time finding a motherboard in the price range I'm willing to spend. I got the new motherboard (used, but "tested and 100% working") installed it, hooked it up with the original power supply. Nothing. I put in the second power supply and it booted! Yay! I finished connecting everything, installed the memory, and hooked it all back up. Now, when I booted it the first time, the bios started, got the LOGO, it checked the processor and the RAM and said "OK". It detected the hard drive and CD/DVD WRs. Then it said "CMOS checksum error". It's shown that error message twice, both times last night. I pressed F1 to continue and it said: "SATA TX2 plus Bios version 1.00.00.20 Detecting...." "Device not found..." "Bios not installed." After that it continued on doing something (it was too quick to see what was going on) and for a split second it looked like it popped up the Windows XP screen and then rebooted. That was the only time I think I saw that. After that I've tried several different things. I checked all the connections. I took the battery out over night and put a different one in. Nothing changed. The board calls for PC333/266 but I just bought 2 Gs of PC400 and had installed that. I took the 400 out and put in one 512MB of PC266. Nothing changed. I have an old hard drive with 2000 Professional on it, so I dug it out, and hooked it up. It goes through the whole process as described before without rebooting and it actually brings up the Windows 2000 Professional screen, but then goes to a blue stop screen telling you to restart the computer. Upon restarting, it shows the LOGO, checks the processor and memory, but freezes when it tried to detect the IDE devices. If I unplug the power from the supply and let it sit for a while it will recognize the hard drive and show the Windows 2000 and blue stop screen. I had gone into the bios and configured it to boot to the CDROM so that I could format the hard drive with 2000 on it, but it always boots to the hard drive, never the XP disk. Having seen another posting with a similar problem, I went into the bios and disabled what looked like the SATA ports. I have Phoenix bios, and I looked under "Integrated Peripherals", and then "Onboard Super IO Function". There I found a reference to "Onboard Serial Port 1" and "Onboard Serial Port 2". So I'm assuming those are the SATA devices it's talking about. I disabled both of those and exited bios. With the original hard drive hooked up, the system booted up and still tried to detect the SATA device and failed. "Bios Not Installed." This time it gave a new error message. "Verifying DMI Pool data... Disk read error occurred" Also, with the old hard drive with 2000 it still hangs up when it tries to detect the IDE devices. I would appreciate any help someone might provide. I'm about to pull my hair out. Thanks so much!