when my computer start that is restarting always, what can i do?

Answer 1

press F8 when your computer is booting. a menu should come up. select SAFE MODE. once in windows go to HELP and type SYSTEM RESTORE. Use system restore to restore your system to a point before it started restarting.

once you have done this,

Open System in Control Panel.
On the Advanced tab, under Startup and Recovery, click Settings.
Under System Failure, make sure that
"Automatically reboot" is not checked.

Answer 2

Do you mean that when you turn your computer on, it never fully boots into whatever operating system you are using?

I'll make a guess that you are using some version of Microsoft Windows. When you turn the computer on, tap the F8 key near the top of your computer's keyboard. When you are asked how you want Windows to boot, choose Safe Mode.

Then follow etheesdad's instructions below.

Answer 3

this can happen if a fan above the processor or inside the smps power supply is not working. Though it can also happen due to a virus infection, you have to find that out
http://mypchelp.blogspot.com/2007/06/computer-reboot-problem.html

Answer 4

It sounds like a driver problem
Boot into safemode and update your drivers

Also, check for suspicious files in your start-up folder

Answer 5

if it goes 2 a blue screen it cud be you have a un atherizor os