Spontaneous freezes and disc read errors on startup

[bendyspaghetti]

Lately my computer has been having fairly spontaneous freezes and sometimes bios gives me a disc read error on startup. I found that switching my hdd's sata port usually allows me to temporarily fix the problem for a day or two. I had this problem before and bought a new hdd, thinking that was the cause of the problem. It's only been about 3 months since I switched hdds, so something else must be the main issue. I was thinking it may either be the mobo or the power supply... any ideas?

 

[bendyspaghetti]

By the way, here is a list my computer's hardware:

*EVGA 122-CK-NF66-T1 LGA 775 NVIDIA nForce 650i Ultra ATX Intel Motherboard
*Crucial Ballistix 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model BL2KIT12864AA804
*OCZ StealthXStream OCZ600SXS 600W ATX12V / EPS12V SLI Active PFC Power Supply
*320GB Western Digital 7200rpm hdd
*EVGA 320-P2-N815-AR GeForce 8800GTS 320MB