boot up problems with newly built system

[dnicholas]

Experiencing strange startup problems about 1 in 4 times when powering up. Will get one of the following boot failures :

1. 'Overclocking failed or overvoltage failed' (I'm not overclocking)
2. \windows\system32\config\system missing (ctrl-alt-del and its fine)
3. A blank screen just prior to when XP would normally start, with a blinking cursor at the top left (although this problem has happened less than 1 and 2)

- A quick tap of Ctrl-Alt-Delete gets things working without further problems. Problems might be happening more on first boot in the morning.
- I can shut down, unplug, wait 30-60secs, plug power back in, start up and get running ok 10 times in row with no problems once things are running
- During operation, system has spontaneously restarted twice during operation of XP pro and applications, about once per week.
- All parts are brand new, brought from Newegg, put together myself.

Any ideas what is causing these problems ?

System description:
Motherboard : ASUS P5N32-SLI SE Deluxe
BIOS : version 0401 (09/05/2006)
CPU : Intel Core 2 Duo E6600 Conroe 2.4GHz
Memory : CORSAIR XMS2 2GB (2 x 1GB) 240-Pin DDR2 800
Graphics: XFX PVT71PUDF3 Geforce 7900GS 256MB GDDR3 PCI Express x16
Disks : WD SE16 WD3200KS 320GB SATA 3.0 gb/s (x2 in raid 1) ; Seagate Barracuda ST3160023A 160gb
PSU : SILVERSTONE SST-ST56F ATX12V/ EPS12V 560W
CPU cooling fan : ZALMAN CNPS9500
Other peripherals : cd/dvd player
Case : Antec Performance I P180B with 3 12cm fans on medium speed
OS : XP pro w/ sp2 and fully up-to-date

Measured power use via a 'Watts Up' meter : between 165-200W
Reported CPU temp : 25-35C
Reported CPU Fan speed : about 1800-2000rpm
Reported CPu Vcore: 1.26-1.28v

BIOS configuration:
Overclocking : none
Memory Timing : 4-4-4-12-T2
Restore on AC Power Loss : Power Off

 

[Apokalipse]

I'd guess it's your power supply

 

[dnicholas]

Thanks. I'm thinking it might be that too, but its not clear how '\windows\system32\config\system missing ' is caused by that - any ideas ?

Also, I replaced an old computer which had psu problems twice in a row and finally died so might it be a problem with the actual power in my office that I'm plugging in to that is to blame ?

thanks again