This sounds like a heat problems to me. Do you have good thermal compound between the processor and the heat sink? Processor fan working? >>> >>> I recently finished my first complete build from the ground >>> up. I am using a ASUS P4R800V-Deluxe motherboard, Pentium 4 >>> 3.0 GHz processor, with a Western Digital 40 GB IDE HDD. I >>> also have a DVD ROM, CD-R/RW and Floppy from my old Gateway >>> computer in it. It's powered by a 450W power supply. At >>> first I ran into some grounding problems with the board >>> contacting the case, but resolved those, and have the computer >>> booting up and posting fine. I originally had 2 256 MB PC3200 >>> DDR RAM from AMPO made from Wintec in the system. I booted it >>> up with the Windows ME startup disk, ran fdisk and format on >>> the HDD just fine, I then inserted my Windows XP Update disk >>> into the DVD-ROM drive and restarted it, it read the CD, began >>> to load the files and when it got to the point when it said >>> "starting windows", the computer just shut off without warning. I trie >>> d the same thing with the CD in the CD-R/RW drive and the same >>> thing happened. I then tried it with the jumper on the HDD on >>> master, cable select, took the jumper completely off, no >>> change. I downloaded memtest86+ and made a boot disk out of >>> it and ran that, and 1 or 2 seconds after the program loaded >>> and began running it the computer shut off. I tried it with >>> each ram stick in the DIMM slot individually and it shut off >>> sooner than it had with both. Though, when I start up the >>> computer and enter the BIOS it reads the RAM and displays the >>> correct amount of memory. This lead me to believe perhaps the >>> RAM was bad. I then went out today and bought a PNY 512MB >>> PC3200 DDR400 RAM and tried that running the memtest86+. The >>> test ran a couple seconds longer than it had with the other >>> two sticks, but the computer still shut off. I tried it in >>> each DIMM slot and ran the test for each one and for some >>> slots it ran longer than others, but inevitably at some point >>> it shut off. I'm at my wits e >>> nd and have no idea what to do, PLEASE HELP ME!!!!!!!! Thank >>> you so much!!!! -Clay The NOSPIN Group has added a new feature on our website, web based bulletinboard for questions and answers: Visit our sister website at http://nospin.com