iMac random freezes and reboots.

I have an iMac mid 2007 2ghz Core 2 Duo, 3gb ram, running Mountain Lion and I've started having a problem. Initially, I would get freeze ups of programs but the mouse pointer would still move around screen. This would seem to mainly happen in the first 5-10 minutes of use and after that all would be okay. I did a verify permissions, it found a couple of things and seems to be worse. Now also out of the blue, I've been in the middle of something and it would just reboot with a message that my computer had recovered from a system crash. I did a disk check and it reported no problems. Anyone got any ideas what is going on? Is it Mountain Lion not playing properly or is something else going on. I'm seriously considering going back to Snow Leopard or even Lion.

 

Thanks for the reply. I read the thread but couldn't see if there is any actual fixes. Maybe I missed it. Any more help would be appreciated.

 

I have downgraded to Lion, let's see how it goes. Fingers crossed.

 

Well, first freeze ups, 2 within 20 minutes. The common factor both times was I had Google Chrome open. More I think about it, this happened before as well. I would use Safari but I think it happened with that as well. I'm now at a loss again.