Why does Linux constantly freeze?

I have Xubuntu 14.04 installed on my computer, which freezes every time I start it after about 10-15 minutes. I have reinstalled the system - the same result. I installed another Linux distribution - Ubuntu 10.04 - the same freezes 10-15 minutes after launch. Boot through LiveCD - the computer still freezes. True, in this case it lasts longer - 20-30 minutes. Windows is installed on the same computer, and there are no such problems with this system. So why does the computer have such problems with Linux?