Asus P5B mobo - new comp wont power up.


Jan 17, 2008
Hi there, im currently building a new computer for my parents and its turned into a little bit of a disaster. I've built a few computers before and never had a problem:

The setup im using is:

Asus P5B (standard) mobo
Intel C2D E6550
2GB (2 x 1gb dual channel) OCZ Nvidia SLI RAM PC2-6400
XFX Geforce 8800 GTS 320mb
Sata HDD
IDE DVD drive
550w PSU

now, the problem is that the computer powers on for a few seconds, turns itself off for another few seconds, and then powers itself on indefinetly. However, there is no RAM beep, only a tone as it powers off the first time, and again if i turn it off by the switch on the case. There is also no output to my monitor.

This problem is alsmost certainly the mobo as i have tested everything else:

- the processor works fine in my other computer
- the 8800 is my old one and works fine, neither does a 7600 GT work
- Ive tried some other OCZ ram to no avail (i cannot check the new ram as my old mobo is not compatible)
- Ive tried a brand new sata hard drive, as well as both of mine
- ive tried a spare PSU (also 550w)

This power problem seems to have happened before, however others have had output from their graphics card.

Any help would be greatly appreciated. Thanks :)