Random Restarts, Restarts when inserting Discs

[Munner]

Hello everyone. Basically, my computer has been getting random restarts lately (30+ in the last month), and the computer also restarts when inserting a disc into the disc drive. I have "restart on crash" or w/e the option is unchecked, but it still crashes.

My computers specs -

Intel Q6600
Asus p5kpl-cm motherboard
4gb ram
ATi Radeon 3650
500 watt Rhino (lol) power supply

I am assuming it is the power supply, and I am going to replace it anyways hopefully as soon as tomorrow, but I am wondering if there could be something else causing the problem. Thanks in advance for any help.

 

[gaidensensei]

Can be the memory as well. If you have any spare sticks around I'd advise to try that, or run some memtests.

 

[oynaz]

The obvious suspect is the disc drive. Try unplugging it as a first measure.