Random restarts and monitor does no respond on cold boots

Hey everyone,

I have just built my first computer. I put it together with a friend, installed the OS no problem. Booted up fine.
The next day I was trying to plug in a USB and accidently hit the clrCMOS button on the mobo. From then my boot up time is longer and the computer randomly restarts. Also, on a cold boot the monitor will not respond and i have to turn the computer off and then turn it back on and it starts up fine

My build:
CPU: Intel Core i5 3570K
Motherboard: ASRock Z77 Extreme4 Motherboard
Graphics: Palit GeForce GTX 680 Jetstream 2GB
Memory: Corsair Vengeance CMZ8GX3M2A1600C9 8GB (2x4GB) DDR3
Hard Drive: Seagate Barracuda 2TB ST2000DM001
Sold State Drive: SanDisk Extreme Solid State Drive 120GB
Optical Drive: Samsung SH-224BB SATA DVDRW Drive
Case: Corsair Carbide 400R Black Mid-Tower Case
Power Supply: Silverstone Strider Plus 600W ST60F-P
Operating System: Microsoft Windows 7 Home Premium 64bit
CPU cooler: Hyper Evo 212
Asus wireless card

My friend told me to check in BIOS if my sata was AHCI or IDE and it is currently AHCI.

Any ideas on any of my problems? I know i could just reinstall the OS but i have already installed everything on it and would be a huge pain to have to start again

Thanks