placed 320gb hdd in 120gb ps3 slim (Hdd seems the be the problem but why!)

Hey, Yeh I got my slim in september along with the 120gb hdd but as I had a 320gb hdd I would rather use that (note this hdd 320gb has been used the fat ps3 I used to have for a bout a year) i noticed that after 30 days from buying the slim and using the 320gb hdd the system crashed and just frozed then i started to use the 120gb but then i would go back to 320gb and just recently It's been working for over a month now and just randomly yes randomly it starts to freeze again.

I know you'll think i've made the answer, but I want to use the 320gb so How do i solve tihs.

Well, I feel like to make sure that it is the hard drive you need to get a 3rd one and use that for a while to compare and diagnose the problem. ( you could always buy an external inclosure to convert plain drives into a usb powered back up drives).

when u bought the 320gb, was it already fat32 formated? or does the ps3 take care of that?

Sounds to me that the hard drive might have been damaged or corrupted to start with. If I were you, I would take it back and get a replacement if you still have the warranty.