My computer froze when starting up! What should i do?

Too little information for anyone to make an analysis. What do you mean by froze? At what point in the bootup process did this happen?
Did you download any programs lately etc.?
Have you tried running in safe mode? Press F8 when it is booting up to go into safe mode. Then it may be possible to determine the problem.

Unplug everything and wait a few minutes. Then restart, always works for me. and I have no idea why.

My laptop, i just bang around a little. Laptops need tough love.