With all of the restoring images from when everything was working and all of the clean installs, it has to be hardware related.
I'm thinking the same thing.
Reseated RAM and vid card, ran Memory Diagnostics.
Called ASUS today, explained the problem. Got escalated to higher level tech support.
Had to send them a bunch of info, will hear back in 24-48 hours.
Everything is still under warranty except the power supply and monitor, and I got a spare power supply, (identical).
If it turns out to be the monitor... that would be bad. only other monitors I got are CRT monitors. :)'
Actually I've whole spare computers, caseless. :)
Like this one... just sitting in pieces..
Windows 7 Home Premium x64 SP1
AMD FX-8350 Vishera 4.0GHz (4.2GHz Turbo) Socket AM3+ 125W Eight-Core Desktop Processor
ASUS SABERTOOTH 990FX R2.0 AM3+ SATA 6Gb/s USB 3.0 ATX Motherboard ( 2901 BIOS)
EVGA 03G-P4-2883-KR GeForce GTX 780 Ti Superclocked 3GB 384-bit GDDR5
CORSAIR Dominator Platinum 16GB (2 x 8GB) DDR3 1866Mhz RAM CMD16GX3M2A1866C9
COOLER MASTER Hyper 212 EVO RR-212E-20PK-R2 CPU Cooler (push/pull)
WD 500GB Velociraptor - SATA III
WD 2TB Caviar Black FZEX - SATA III
WD 2TB Caviar Black FZEX - SATA III
WD 2TB Caviar Black FZEX - SATA III
LG GH22LS30 CD/DVD Burner
And this one...
Windows XP Pro 32bit w/SP3
ASUS M4N82 Deluxe nVidia 980a SLI Motherboard, (2501 BIOS)
AMD Phenom II X4 955 Black Edition 125W stock:3.2Ghz OC'd to 3.7Ghz
EVGA 015-P3-1580-AR GeForce GTX 580 (Fermi) 1536MB 384-bit
Corsair CM2X2048-8500C5D Dual Channel [5-5-5-15-22-2T-2.1v]
WD 300GB Velociraptor SATA II
WD 1TB Caviar Black SATA II
WD 1TB Caviar Black SATA II
LG HL-DT-ST DVD-RAM GH22LS30 CD/DVD Burner SATA
The only good thing about this problem is that the computer runs... fine, except for the no BIOS splash screen and the sometime delay after entering the password on the Welcome screen.
/edit
And this one, is even still assembled...
Windows XP Pro 32bit w/SP3
ASUS M2N32-SLI Deluxe Wireless Edition AM2 NVIDIA nForce 590 SLI MCP ATX AMD Motherboard (1603 BIOS)
AMD Athlon 64 X2 5000+ Brisbane 2.6GHz Socket AM2 65W Dual-Core Black Edition Processor (OC'd @ 3.2Ghz)
CORSAIR XMS2 (2 x 1GB) 240-Pin DDR2 800 (PC2 6400) Dual Channel Memory Model TWIN2X2048-6400C4DHX
EVGA 01G-P3-1280-AR GeForce GTX 280 1GB 512-bit GDDR3 <-- Ran this for most of the time.
EVGA 256-P2-N758-TR GeForce 8600GT SSC 256MB 128-bit GDDR3 <-- Ran this after I built, my AMD Phenom 955 build.
WD 36GB 10,000rpm Raptor SATA
Seagate 80GB 7200rpm SATA
Lite-On LTR-52246S CD/RW
Lite-On LH-18A1P CD/DVD Burner
PC Power & Cooling Silencer 750 Quad (Black) EPS12V 750W
ZALMAN 9500A 92mm 2 Ball CPU Cooler 45 CFM at 27db (full speed)
Generic Mid Tower case w/ 5x 80mm case fans [ 2x front intake, 2x rear exhaust, 1x left side exhaust]
ViewSonic G90FB Black 19" CRT Monitor