Game Crashes Failed Boots / Random Restarts Hard Hangs

[code] Now here is what has been going on since 26/05, While I was playing "World of Tanks" the game froze, sound was stuck and screen turned black with white stripes, I had to force a restart, the minidump was accusing a dll file of nvidia's which when I searched for on the internet it sounded like a random hiccup of Nvidia and it only happened once so I ignored it. But the game started crashing to the desktop since then but not very often, it never did that with my older pc, so I don't know if it's from the game side or my side.Yesterday around 8pm, I was about to transfer a 7gig folder from my main disk to the storage disk, as soon as I opened the partition that I was transfering to, I had a blue screen saying only "Unknown hard error", I force restarted and the MB resat the Bios and it restarted again and since then windows wouldn't boot, it kept asking for repair and during that repair it said "System was unable to boot" several times and after the many repair runs it kept saying it failed to fix the problem.Then I unplugged my storage HDDs and only left the system HDD, booted from windows 7 DVD and tried to repair but still said it couldn't fix the problem, in the report it said there was a problem with ci.dll, so I started "command" tried these commands (bootrec.exe /fixboot, bootrec.exe /fixmbr, bootrec.exe /rebuildbcd) after that I restarted and windows booted perfectly, right after that I shut down the computer, plugged in the 2 other HDDs, windows booted perfectly then all of the sudden, the keyboard wasn't responding (not even it's leds were working) same thing with my mouse, I looked at the HDD led and it wasn't doing anything at all, no small flickers or anything, so I force restarted, it booted like normal, I started to transfer a folder to 1 of my storage HDDs, opened up firefox, it was acting really slow, everything I was doing on it was lagging although nothing was draining the CPU or ram or anything, opened few pages, when the transfer was about to finish, the pc restarted.

After the restart, the event log says "kernal power" event id 41, category 63 and it didn't give me any minidumps. Anyway I went to sleep around 3AM, left my downloads running and was hopping nothing would happen but something sure happened, the event log says at 4:30 AM "The Windows Modules Installer service entered the stopped state." then no new events till 6:45 AM which was a warning saying "TCP/IP has chosen to restrict the scale factor due to a network condition. This could be related to a problem in a network device and will cause degraded throughput." No other events till I had waken up at 10:37 and found the monitor turned off not responding, HDD led completely off, no flickers, basically nothing was responding.So here I'm don't know what the hell am I supposed to do, I have a decent knowledge regarding windows problems, but this problem is too open and wide, is it 1 of my hard disks? is it the lonely GPU I have right now? is it the ram? is it the CPU? I need some guidance on how to eliminate each of them.before the MB resat the Bios, the CPU was overclocked to 4.2GHz and I tested it many times and it was very stable, so when the system hanged after the boot problem was fixed, there was no overclocking involved, there was no heating issue, temps were normal, I have a 1000w plus gold certified PSU.