CPU heats up then no app will run

[Jaster]

For the past 3 nights my CPU suddenly heats up for about 30 seconds making the fans excessively loud. Then after it cools down no application nor file will open. A restart solves the problem but I'd rather know why this is happening.

Any ideas?

 

[Eidorian]

I'd keep Activity Monitor open showing All Processes sorted by %CPU all the time.

 

[Jaster]

I'd keep Activity Monitor open showing All Processes sorted by %CPU all the time.

Looks like I'll have to do that. I saw Safari heating up the CPU one night but I couldn't confirm it again as Activity Monitor was accessible.