Repeated boot failures

About two weeks ago I started having boot problems. I cannot relate it to any particular event like a new program or update. My system information is listed below using Piriform Speccy - this is a home built system and has functioned fine for about 18 months. I have had it set up to schedule shut downs at night using my CyberPower 1000 UPS. I would simply restart in the morning. Worked fine for over a year.

Two weeks ago the machine would not restart. It hung on black screens (dual monitors)and the hard drive light showed no activity. After a number of hard reboots the system started normally. This now occurs every time the system is shutdown or restarted. The hang point varies. About 90% of the time the screens simply remain blank and boot stops. Sometimes it I will get a blinking cursor on the #1 screen and other times it will get as far as the Windows start (the POST shows no errors I can see)and freeze before the colored balls come together. When it does successfully boot it runs apparently without problem.

System Information:
Operating System
Microsoft Windows 7 Ultimate 64-bit SP1
CPU
AMD Phenom II X4 955 47 °C
Deneb 45nm Technology
RAM
8.00 GB Dual-Channel DDR3 @ 666MHz (9-9-9-24) - Patriot Sector 5
Motherboard
ASUSTeK Computer INC. M4A79XTD EVO (AM3) 43 °C
Graphics
SyncMaster (1680x1050@60Hz)
DELL E207WFP (1680x1050@60Hz)
AMD Radeon HD 6700 Series (XFX Pine Group)
Hard Drives
466GB Western Digital WDC WD5001AALS-00E3A0 ATA Device (SATA) 42 °C
466GB Western Digital WDC WD5000AAKS-00WWPA0 ATA Device (SATA) 36 °C
Optical Drives
PLEXTOR DVDR PX-L890SA ATA Device
PLEXTOR DVDR PX-880SA ATA Device
Audio
VIA High Definition Audio

I suspected, after reading some threads, it might be a bad stick of RAM. I ran the Windows memory diagnostic and it showed no problems. I also pulled all of the RAM and tried each stick in the #1 socket. Initially I thought I had found the problem when I got a successful boot with only the original stick in the #1 socket. All the other sticks failed to boot. That made me suspicious. Retesting the first "good" stick resulted in a failed boot. I replaced all the RAM.

I ran chkdsk and it showed the drive to be clean. No issues were reported.

I ran sfc /scannow and it returned "Windows Resource Protection found corrupt files but was unable to fix some of them." I reviewed the log file and as as near as I can tell most of the files that could not be repaired have to with games - which I don't use. I've attached the sfc log.

I also attempted do a reinstall of Windows 7 Ultimate from a CD, but it would not load because the current version is newer. I am assuming that means because my updates are loaded. I will try again, but choose the option to look for the latest version of Windows 7 online.

I should also point out that I am running Bitdefender Total Security 2012 with daily checks and it identifies no problems.

One other thing. When the system is hung, soft reboots and hard reboots are generally ineffective. The system just goes back to black screens and stops. But, if I pull the power cord and wait until all the board lights are out, the next attempt gets me to at least the POST screens. The system may or may not successfully launch Windows, but it gets to the Windows start up. A subsequent hard boot usually gets a successful start.

Yea, I'm confused. Any help would be welcome.

You were not doing a Clean Install Windows 7 if it yielded that error, but were running a Repair Install which is an in place Upgrade over itself.

Test the HD with maker's diagnostics CD and RAM with memtest CD for 5-6 passes given in Troubleshooting Windows 7 Failure to Start .

Then work through the other steps to attempt to repair Startup after confirming Active partition. If you'll post back a maximized Disk Mgmt screenshot showing drive map and all listings we can look it over for you.

The steps lead up to if necessary a Clean Reinstall - Factory OEM Windows 7 which steps are the same for retail, will yield a perfect install if you follow them closely, and provide the latest installer to use.

Thanks for getting back. I do understand that I got the error notice when I tried to repair install of Windows 7. I really wanted to avoid a full clean install. I ignored the recommendation to go on-line and find an updated version. So, my CD had none of the updates that the version on my PC has. I assume that was why it was determined to be an older version and the repair install/upgrade was terminated. Question: if I do go on line during the installation and download the latest version of Windows 7, as directed, would the repair install work - or at least complete?

I will do the HD and RAM tests, but I'm thinking this is something to do with the software and not hardware. If the RAM is bad all four sticks went bad about the same time. I think that's pretty unlikely. But, I will work through the steps you suggested.

One other thought I'd like an opinion on. I have a second HD installed that is unused. Is there any reason I couldn't do a clean install of Win 7 on the second HD, boot from it for a while to see if that solves the problem and still access all my programs and files on the my C: drive?

What solves the problem with Repair Install most commonly is using the latest official Win7 installer for your licensed version which I linked in prevous post.

Yes you can run a test install to another HD to see if it's hardware related, but I would run the Repair install first to see if that sets it right.

Got it. Thanks, that's the way I'll do it.

I ran the WD diagnostics and the HD passed. I attached screenshots of the results. I work on the other recommended steps Sunday.

Mark, it's kind of funny, I started using WD drives about 10 years ago because of a series of bad experiences with Seagates dying young. I've always had good luck with WD.