Building computer question help!?

So I just put together my gaming computer. Worked great started right up, then i set the bios to boot from cd. Restarted put in my windows 7 cd. Windows 7 started to load, got to 43% and did a restart loop. when restarting computer asked if i wanted to boot from harddrive or disk i let the timer run out so it would continue on. comp instantly turned off, attempted to re turn on like 2 times and now it will not turn on no matter what i do. onboard led light is on on the mo board and the lights are on on the graphics card. What did i do wrong!!!?!?!? someone please help me!!!