Hello, I have been asked to fix a PC by a friend but I am afraid it has gotten a little beyond my knowledge. This is an emachines w5243 windows vista machine. Onboard gpu. Upon powering on, the machine receives power and then will shut off a few seconds later. If I try this a few more times, the machine will stay powered on. I can access bios and some other settings. If I then attempt to boot, as soon as the bar for windows starts loading, the machines either restarts or powers off. The same thing happens in safe mode. I have swapped power supplies, no difference. There are 2 sticks of ram and I booted with one at a time, no difference. I have reset the CMOS battery, same. In the hopes of a corrupted windows installation, I swapped around the hard drives. Plugging the eMachines into my own PC, I was able to access the hard drive (and cleaned it up a bunch while I was there...apparently the pc belongs to the woman's kids for the most part. Infections from hell! Cureit got most everything I think. That is besides the point though.) I plugged my windows 7 hard drive into her computer and the symptoms were repeated. I was able to tell it not to restart on errors and got some error codes from a BSOD. 0x0000007b (0x80786B58, 0xC0000034, 0x00000000, 0x00000000) Researching that points to drivers/device conflicts. But I have ran with bare minimums already and swapping hard drives should have eliminated any possible driver conflicts. (all drivers would be stored on the hard drive if I am not mistaken?) I am able to run an older version of Ultimate boot cd up to the menu screen. (I'm doing a ram test now, although I figure it will come back fine. I'll edit if I find different.) EDIT: It ran memtest86 for an hour, it completed test 1 with zero errors. I'll let it run longer later. However if I attempt to run the Ultimate boot cd program itself, a windows logo pops up and then the PC crashes. I grabbed the newest version of UBCD and that crashes before I can ever get to the menu even. Also, if I attempt to open or close the CD tray while it is booting, it will always crash it seems. That would seem like a power issue, but again, that should have been eliminated with swapping the power supply. Does all of this point at the motherboard being bad? Is there anything else that might cause these symptoms? Shorts, wiring? (If you can't tell I'm trying my hardest to avoid the inevitable yanking of the motherboard and taking it to a repair shop to have it tested.) Are there any further steps someone can recommend me taking? Is there an easy way to test the motherboard at home? I am no hardware expert but I might be able to borrow a multimeter from my father if that might help me somehow. Any advice is appreciated. Thanks!