Your board appears to be the P7 H55E. At least that's what yout Bios idebtifies it as. The size of the power supply has nothing to do with the size of the motherboard.
Cross checked bios setting with my son's pc which has the same hardware as mine. But we discovered he has the p7h55-m board running bios 1101. He's upgrading his rig soon and when he figures out which new motherboard to get i might nab his old one!
Meanwhile - are we running out of options here do you think?
My Computer
At a glance
Windows 7 Professional 64 bitI3 530 2.93 ghz8 gbGE Force GTS 450
Just found this FAQ on the asus site ASUSTeK Computer Inc. -Support- FAQ for my board - is it worth trying as it wont boot in AHCI mode nomally?
install win7 in IDE mode,then change to AHCI,OS would be blu screen,how to slove?
Solution
1. Run regedit to open registry
2. Locate HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ services \ msahci
3. In the "Edit DWORD Value " dialog box, the "Value data " box, the value of the number from 3 to 0 (Figure 2), click "OK" button
4. Close the "Registry Editor " window and restart the computer.
5. Restart your computer when you enter the BIOS settings screen, change the hard disk AHCI mode
My Computer
At a glance
Windows 7 Professional 64 bitI3 530 2.93 ghz8 gbGE Force GTS 450
Power outages and or power surges when the power is restored can cause motherboard problems when a poor quality power supply is used. It is more possible when a surge protector is not used.
A quality power supply has a higher quality low and high voltage spike protection built in. Lower priced motherboards are more susceptible to voltages variations also because they have fewer capacitors.
I recommend a surge protector even when using a quality power supply.
Sometimes trouble shooting these problems is almost impossible without a lab designed to do such testing.
My computers and everything that hooks to my computers has a surge protector used.
A few bucks can save someone thousands of dollars worth of equipment.
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I have installed Windows 7 AHCI and IDE so I do agree with Steve that is probably not your problem.
It can't hurt to try both ways to the best of my thinking.
My Computer
At a glance
Windows 10 Pro. 64/ version 1709 Windows 7 Pr...Intel i7-6800K @ 4.3Corsair Platinum 16 gig @2400EVGA GTX 1070 OC
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Home made Desktop
OS
Windows 10 Pro. 64/ version 1709 Windows 7 Pro/64
CPU
Intel i7-6800K @ 4.3
Motherboard
ASUS X-99 Deluxe II
Memory
Corsair Platinum 16 gig @2400
Graphics Card(s)
EVGA GTX 1070 OC
Monitor(s) Displays
Asus 27" LED LCD/VE278Q
Screen Resolution
1920-1080 or 1280-720 HDMI
Hard Drives
INTEL SSD 730-240 Gb Sata 3.0/
PSU
EVGA Platium 1200W
Case
Phanteks Luxe Tempered Glass 8 fans/ one radiator
Cooling
XSPC/ Water Cooled CPU
Keyboard
Das 4 Professional
Mouse
Logitech M705/MX Anywhere 2-S
Internet Speed
100 mbits
Antivirus
Microsoft Security Essentials/ Malwarebytes Premium 3.0/ SAS
Browser
I.E. 11 default/Firefox/ ISP Time Warner Cable/Spectrum
Other Info
LG BluRay Burner/
Sound system-KLipsch-THX/
Icy Dock ssd Hot Swap bays.
Every thing I have seen or posted in this thread has shown the bios as 0504. Everything I can find online indicates that is the proper bios. Now can the bios be corrupted most likely NO but anything can happen with power surges. I would also suggest not to assume that a power surge only effected one piece of hardware. Power surges can also effect the video card bios.
I can not over state the importance of proper power and power protection.
If it sounds like I'm beating a dead horse to death so be it.
I think I will get some more coffee and sweeten with a little J.D. this time.
My Computer
At a glance
Windows 10 Pro. 64/ version 1709 Windows 7 Pr...Intel i7-6800K @ 4.3Corsair Platinum 16 gig @2400EVGA GTX 1070 OC
Computer type
PC/Desktop
Computer Manufacturer/Model Number
Home made Desktop
OS
Windows 10 Pro. 64/ version 1709 Windows 7 Pro/64
CPU
Intel i7-6800K @ 4.3
Motherboard
ASUS X-99 Deluxe II
Memory
Corsair Platinum 16 gig @2400
Graphics Card(s)
EVGA GTX 1070 OC
Monitor(s) Displays
Asus 27" LED LCD/VE278Q
Screen Resolution
1920-1080 or 1280-720 HDMI
Hard Drives
INTEL SSD 730-240 Gb Sata 3.0/
PSU
EVGA Platium 1200W
Case
Phanteks Luxe Tempered Glass 8 fans/ one radiator
Cooling
XSPC/ Water Cooled CPU
Keyboard
Das 4 Professional
Mouse
Logitech M705/MX Anywhere 2-S
Internet Speed
100 mbits
Antivirus
Microsoft Security Essentials/ Malwarebytes Premium 3.0/ SAS
Browser
I.E. 11 default/Firefox/ ISP Time Warner Cable/Spectrum
Other Info
LG BluRay Burner/
Sound system-KLipsch-THX/
Icy Dock ssd Hot Swap bays.