Start up infinite loop, cannot get into command prompt. HELP!!!

Hello,

First time poster, I'm in need of some serious help A couple of days ago my custom built computer restarted (I wasn't in the room so I cant tell you guys why it restarted), and went in an infinite start up loop. It kept giving me 2 options and whichever option I choose its the same thing all over, if I chose Load start up repair, windows will unload the file and goes into a black screen, and sometimes it will go on a blank log on screen without the login boxes but with mouse cursor. On the other hand if I chose the start windows normally, the computer will try to load windows but will restart at the end. I have been scouring the internet for solutions and have tried various methods but with no avail. Here are the list of the troubleshoots that Ive tried:

*I made windows repair disk=> after the language option it will just give me a blank screen, cant shift+f10 to get to the command prompt
*put in the w7 installation disk=> repair computer->language option->blank screen, cant shit+f10
=> reinstall computer->stuck on setting up windows for hours
*f8=>repair your computer->loop
=>safe mode/with networking/with command prompt->windows would try to load but in the end blank screen
=>last know good configuration->loop
=>restore mode->loop
=>disable automatic restart->loop
*seagate diagnostic tool=>found some problems but was repaired, still couldn't escape the loop


specs of the computer if needed:
w7 ultimate x64
seagate baraccuda 1tb
msi z77a-g45
intel i5-3540 @3.10 ghz
mem size 8192 mb

HELP PLSSSS!! Id rather not purchase hardware but I will if I have to.