New PC Suddenly Died

[Fry750]

Hello,
I recently built a PC from scratch and it worked fine up until 10 mins ago.
I used my monitor with my Xbox 360 and PC. I unplugged my 360's VGA cable, plugged in my PC's and the display was there then it vanished. My monitor was left saying "No signal input". I haven't a clue what's wrong with it but it stops after the BIOS image. The TAB screen says "CMOS checksum error: Defaults Loaded", i press F1 to continue and it stops at a screen saying Copyright SiI or something.

CPU: E6600
Mobo: Abit IN9 Wifi MAX
GFX: ATi Radeon X550
RAM: Samsung DDR2-5300 1GB
HDD: Seagate Barracuda 320GB SATA II

PLEASE HELP!!! Thank you for taking the time to read

 

[Big B]

I'd start by clearing CMOS (refer to your manual on how to do this)

 

[TMM M45T3R]

i used to have some problems involving the screen when i had that exact card (x550), but i dont know what the copyright siI is about, i have come across messages on bootup before that i havent got a clue about, most of them were to do with my hard drive tho, but like Big B said, try flashing your bios first:P