Windows 7 Will Not Start After Uknown Crash?

so this problem started a few days ago while i was watching a Internet video, for no apparent reason the video froze and the sound started lagging over a few seconds (audio slowed down), then my computer went completely unresponsive and the only way i could turn it off was by unplugging it. once i turned it back on i noticed the motherboard splash screen was a bit pixelated and distorted, and every time the computer goes to the win7 splash screen it loads the little windows icon animation but then when it begins to transition to the login screen, the screen remains black and hangs and never makes it to the login screen.i have a spartan brand laptop (a few years old) with a intel dual core cpu, phoenix technologes motheboard, running windows 7 professional and an nvidia gefore go 7600 video card.once this problem occured i tried numerous attempts to fix it.

1. i tried to run a system repair and the only error i got was something about a patch being the cause of the problem, i proceeded to delete windows patches through safe mode but this did not solve the problem.

2. i attempted numerous system restores to all the dates available to me via safe mode but win7 still does not strat up.

3. i used the repair tool to repair to the most recent point of good working configuration but this did not work either.
i've also run a chkdisk or whatever it's called. it took a while so i left the room to do something else, when i returned i had assumed it finished and restareted my computer because my laptop was hanging on the black screen after the win7 splash screen as usual. the odd thing is, is that i can use safe mode as well as safe mode with networking (which i'm using as i type) and i've also reinstalled windows once while keeping my files and a second time as a completely clean installation. when i've reinstalled win7 both times it goes straight to the desktop after the installation and the computer works completely like normal. i can install things, use the internet, everything. the problem is that some of my drivers are not installed (like the video card) and when i install them i have to restart my computer, and when i restart the computer hangs like usual after the win7 splash screen and i'm back to square one.i don't unserstand why everything works normally but i just can't get past the splash screen. after my second installation of windows7 i ran the repair utility again and the only error i get is that there is an "unspecified error due to changes to the system configuration."