Windows failing after overclocking! Help!

[NargBlarg]

Hey everyone.

First off here are the specs:
Gigabyte Z68-AP-D3 Revision 1.0
i5 2500K 3.3ghz stock
Windows 7 64bit pro edition

So here's what's happening. I've had this setup for 2 years now, running at 4ghz solid for the majority of the two years. No problems. Just recently, I just upgraded my cpu cooler and started pushing toward 4.5ghz. It worked ok but was a bit unstable (got the blue screen of death) so I rolled back to 4.4ghz which seemed to be alright. The next day I got greedy and wanted to push to 4.6ghz which ended up screwing things up (got the blue screen of death but it didn't go through the disk dump that usually happens) so I shut it off manually. At this point, my PC was going through a loop of turning itself on, trying to POST, but POSTing fails and it shuts; this looping was infinite. Clear CMOS to the rescue! The looping problem is solved thankfully HOWEVER, when windows starts loading up, before the "starting windows" splash screen, windows pops up with " Windows Error Recovery: A recent hardware or software change might be the cause." (this: http://www.symantec.com/business/support/library/BUSINESS/ATLAS/images_v1/354479/boot-error1-small.jpg)
So, when I select start windows normally, it freezes at the "starting windows" splash screen, attempts to display a blue screen of death but cuts out every time within half a second and restarts back to POST.

I've tried messing around with BIOS settings and haven't had any luck getting past "starting windows" screen to get to the login screen. Now is this:
1. A BIOS issue? Maybe Load CMOS from BIOS could fix it?
2. A windows issue that could be solved with reformating?
3. Maybe needs the CMOS battery to be removed for an hour or so?

I've tried loading fail-safe defaults in the BIOS with no luck

Thanks everyone!

[Air]

Have you tried using the Startup Repair option? It may or may not fix your issue but it's worth a try.

[NargBlarg]

Yes I have, I just tried it again right now and it didn't do anything for me :(

I'm wondering if there is anything I can do in Safe Mode also

[Big Al]

To be clear, did you return the CPU to it's original clocks and still Windows won't start? I know you said you cleared CMOS, but just confirm in BIOS that the CPU is now at it's stock clocks.

Also, it's not uncommon to have to run startup repair twice or more.

I'm assuming you don't have a backup system image, do you?

[NargBlarg]

"Startup Repair cannot repair this computer automatically"
Problem signature
Problem event name: StartupRepairOffline
Problem signature 01: 6.1.7600.16385
Problem signature 02: 6.1.7600.16385
Problem Signature 03: unkown
Problem Signature 04: 21199639
Prob sig 05: AutoFailover
Prob sig 06: 3
Prob sig 07: NoRootCause
OS version: 6.1.7601.2.1.0.256.1
Locale ID: 1033

Oh yes, forgot to mention that. I did return it to stock clocks and I sadly don't have a backup system image :(

[NargBlarg]

Ah, I didn't pull out the battery, just jumped the CMOS clear. I'll have a go at that. Also, I've been watching temps and they weren't an issue (running on water cooling) and haven't touched voltages AT ALL

Also, is it possible to corrupt the OS after overclocking? I've found in the past that clearing the CMOS should resolve the instability: I'm totally puzzled as to why Windows would be all messed up just from going over board with overclocking

[Big Al]

If Startup Repair is failing, I would boot to the recovery console and check the disk first. Then try the Startup Repair again.

[NargBlarg]

I have a Corsair TX650M for my PSU and no voltage tweaks so that eliminates any power issue. Tried a system repair in safe mode with my windows 7 install DVD and no luck so far.

[rotNdude]

Of course you can corrupt the data on a disk drive when overclocking. When your components can't properly write the data to the disk, you can seriously affect the MBR and any files.

[NargBlarg]

Ok gotchya, seems like the only thing left is reformatting, yes? Both system repair and system restore didn't do anything

[_I_]

before overclocking
what cpu cooler do you have? stock isnt going to get very far
keep the fsb/bclk at 100 (never go over 105)
whats the cpu multi?
whats the cpu core voltage?
did you disable power savings, and c1 states?
how many dimms are you using and whats the ram voltage?

good guide here for the 2g i5
http://www.overclock.net/t/1100100/info-intel-2500k-2600k-overclocking-tips

if windows got corrupted, best to reinstal windows, and run chkdsk full scan to make sure there are no disk errors

[NargBlarg]

Yea, seems like Windows is corrupted. I don't want to reformat as there are a few things I would liked to back up but I guess this is what I get for not backing those things up before going over board/experimenting with higher speeds (I was hoping there was something I could do via BIOS settings to prevent a reformat but I see that it's unrealistic). I have an Antec Kuhler 650, and voltages of any kind were not adjusted (this was at 4ghz) and I didn't touch power savings or C3/C6 states. Ram voltage is set to auto as well (again, at 4ghz and not at 4.5 and 4.6 ghz) so I see what noobery I have committed by boosting the multiplier to 4.6ghz without adjusting the appropriate voltage settings (and also not aware that I could corrupt my OS in the process which has never happened to me-although I've never gone this high up in processor speeds) haha

Anyways, I think it seems clear now that I just destroyed my OS so I'm just gonna say screw it and reformat and will be proper and methodical should I want to go past 4ghz

Lesson learned BIG TIME, thank you everyone for dealing with my noobery!

[Big Al]

Make sure to create regular system images this time. I cannot tell you how many times that's saved my rear in the past.

I would recommend Acronis True Image.

[NargBlarg]

Ok Pltwngs, I'll definitely get that and will back up my things before I experiment with higher clock speeds next time.

[_I_]

you could have used puppy linux to test or memtest86+
any overclocking errors cant hurt those

[NargBlarg]

I see; a right of passage then hehe. Thank you and thank the internet gods for forums :P