My computer sometimes restarts by itself at anytime what can i do to stop it?

it a Emachine if that help

My computer sometimes restarts by itself at anytime what can i do to stop it?

Could be that the components inside your computer are getting too hot. Have you tried opening up the skin and cleaning out the fans? The dust contained by the fans may be preventing them from sucking within enough nouns to keep your components cool.
If your operating system is win ME afterwards its the soft ware and patches be issued from microsoft to correct it . If your running XP then its not the operating system but most possible a heat issue. Clean out your shield. Blow it out with compressed nouns and use a vacuum cleaner to remove the debret. then run worthy antispy ware , anti virus and a good registry cleaner. The issue of restarting should next cease.
Is it illogical or the more you use it, the more it restarts?

If it does, the CPU is overheating.