power on pc, gets half way through so screen then powers down. In safe mode it only gets a little way then powers down.

Stripped back to mobo, CPU, video, 1 hd, ram

Used other psu, same prob.
Switched boot drive to vista machine as secondary, backed up some stuff off it
Made it primary, booted, same powerdown prob
Made it into safemode, installed mb drivers, rebooted
Powerdown problem still occurs

Said f*** this, must be bad windows install, plugged drive back in main connect dvddrive boot off vista DVD planning to do fresh os install, it powers down barely in to it

Ripped out hd, boot off DVD with no hd connected, get to install vista/memory test screen, before I make selection it powers down

I used different power points, diff cables, keyboard, mouse, monitor. I have no idea what is wrong.

Heat Issue?

yeah check bios settings for temperature failsafe settings

Wouldn't hurt to try some different ram too... but don't get that "duel channel" stuff.

what's the opposite of a heat issue? It is normally on all the time, but this week it has been powered off overnight as guest are sleeping in that room. It was this mornings poweron when it first failed

If it is related to that why does it affect both computers? The 2nd of runs fine with the main pcs hd as a slave

thanks I will try bios temp settings tomorrow, I am to annoyed to work on it any more tonight

motherboard has let go?

Fan on My Boxes Vid Card died the other day, its hard to find a fan relpacement for a 5 year old card :/

Dont know if you use SpeedFan but it's a handy little program to see how things (Fan and Temps) are running when you get into windows too.

dude.. had this same problem a couple of months ago. tried everything and got so frustrated that I even contemplated buying a new computer.

I eventually figured out that it was a power issue, because every night before I go to bed I turn the computer off at the wall. So one night I left it on, and voila! the next day it worked... dont know how but it worked so I was happy.

Other than that, about a year ago my friend had the same issue on his comp, it wasn't like mine but it was the same issue that you had. So all I did was reboot the cmos, took the battery out for a minute then stuck it back in. and... it worked!

virus? any fans running? system beeps?

I had same problem, I think in the end i had to replace the power supply, but when i was looking it up people mentioned that the bios battery had run out and that was an issue.

Also it was also mentioned that the power button may have had a problem and that it wasn't connecting properly, so thats some more stuff to try for you.

does it completly power off ? or just restart.

My aunts Dell laptop f***ing shat itself after VISTA SP1 Update.

some f***ing random file on the hdd has an error on it and does not matter if u run the windows DVD or recover cd what, because it always check for that file for hard drive integrity or some s*** it was insta restarting.

Manged to fix it by booting into ubuntu and removing the f***ed file in question $TxfLog im some obscure windows directory
> http://bsods.com/content/windows-vista-and-stop-0x0000c1f5-linux-anyone

Dont know if you use SpeedFan but it's a handy little program

Careful with software like that. It doesn't play nice with all hardware.

I was getting daily freezes on my previous PC. Many formats and hardware replacements later I found that it would only crash randomly if SpeedFan was running. If that program wasn't running in the background, the PC never ever crashed.

Solution? Run SpeedFan only when I needed a reading, close it immediately.

My current PC doesn't have this problem, luckily.

but when i was looking it up people mentioned that the bios battery had run out and that was an issue.

Well the battery is the only thing keeping the bios settings alive since it's in volatile memory, having to keep it alive for months/years. I usually reset my settings every year or so just in case some of the data is corrupt. Sure the checksum is meant to pick up errors, but still.

I had a motherboard that died just recently and it would boot up, and then shut down again before it would even post.

I thought it was power / heat etc... it was actually the motherboard.

Tried booting off a livecd like damn small linux? If you can boot into (and use for periods of time) a substitute desktop OS, then you can probably rule out your hardware as being at fault.

How old is the Mobo/PSU? Make /Model etc...
Cast an eye over both components an check for caps that are bulging or popped. Alternatively, check your PSU output if you can.

try scanning your ports

Mobi ram CPU is 1 year and 19 days old.

I suspect it is mobo, so I am going to properly pull it out and reseat everything this weekend. Like the live cd idea. Will try that. Have replacement mb arriving Monday