Hi all. As I recently upgraded my system (Asus Z87-A board with Intel i7-4770k (Haswell)) and I've been testing different overclocks. I have been careful with my OC'ing method, only increasing frequency by a small bit each time (100mhz) and increasing VCore by 0.025v each time I get blue screen. I'm certain the blue screen is a VCore issue because I've researched on the net that error 124 in blue screen refers to a lack of VCore voltage.
Anyway, I got blue screen a few times (as you do) when trying to overclock. I assure you that I have a strong air cooler (Scythe Mugen 3) so my CPU never reached +85c temp and I found that I can't go beyond 1.3v-1.325v because then the temp would go above 85c. At the moment, I've decided to keep my CPU at 4.5Ghz @ 1.275v.
To get to the point, after a few blue screens, my Windows got corrupted as it wouldn't boot. As far as I remember, it was due to an "Invalid Partition Table" when it tried to boot the OS. I then attempted to install a fresh install of Windows but once my installation just crashed and another time, it installed but then I got a bootmgr missing error so as you can imagine, I was freaking out . Eventually, after a few attempts, I got it installed and managed to boot into the OS. The issue now however is that whenever I get a BSOD, due to using the adaptive VCore option which automatically increases VCore to 1.275 (but I set it to 1.220v because AIDA64 stress test for some reason bypasses the setting so 1.220v adaptive translates to 1.275v when AIDA64 stresses the CPU is running at firstname.lastname@example.org and keeps it at default 1.017v when the CPU is running idle. Windows seems to take it's sweet time to boot (as in it takes a long time to see the "Starting Windows" screen).
Anyway, I had left the adaptive at 1.220v and I was playing Batman Arkham City normally, without issue when suddenly I got BSOD (error 124) which I assume is because it was running at 1.220v and that wasn't enough for 4.5Ghz.
I then tried to to do the regular bootrec /fixmbr, /fixboot and /rebuildbcd but for fixboot and rebuildbcd in the command prompt from the Windows 7 DVD, I get an error "Element not found" so the installation is messed up somehow after getting BSOD. This is also because the installation wasn't detected when I accessed the Repair Your Computer screen. I also tried to do Startup Repair where Windows attempted to fix it but ofcourse, it didn't fix it. I then checked the diagnostics of the repair and found the error "The partition table does not have a valid system partition".
I tried to eliminate the cause by installing Windows on another HDD I have. I got BSOD but it worked fine, it booted quickly as it did before the BSOD, even switching SATA cables to see if it was motherboard related or cable related but it was fine so motherboard isn't the issue. So now I'm thinking something is messed up with the partition table/boot sector of the HDD so what is the best way to fix this? I can't afford to format the whole HDD as I have important files on my data partition. So what can I do to fix the boot sector or partition table? Thanks and sorry for the long post but I just felt that I needed to explain the process I went through.
OS: Windows 7 Ultimate SP1 (x64)
Motherboard: Asus Z87-A motherboard
CPU: Intel Core i7-4770k (Haswell @4.5Ghz)
GPU: 2GB Gigabye NVIDIA GTX 670 Windforce 3x @ stock clock/memory
HDD: Problem drive: Seagate Barracuda 720014. 2TB 3.5" SATAIII HDD (ST2000DM001) / Working drive: 500GB Western Digital Caviar Blue SATA HDD (WD500AAKS)
PSU: Corsair HX850 V2 power supply
Honestly i would take the drive to another computer and run recovery on it. Make 2 copies your important data then you can try an upgrade install and if that doesnt work your off to a fun filled evening doing a full reinstall. Backups are the only resource you have to save your important files. When you mess with your system you make a fresh backup before you start just in case.