Mid 2010 MacBook Pro Freeze's

I have a macbook pro i7 2.66 Ghz, 4 GB RAM, 500 GB HD. Never had a problem till I installed Mountain Lion. Every now and then my my computer freezes. Hard drive won't stop running even if it's on sleep mode. It's **** frustrating. Now with this hard drive running non stop and with the system freeze's every now and then i fear that it will damage some other hardwares due to this problems. Is there anybody know's or have any solution with this problems? Thank you! Appreciate it.