Windows 7: Computer not working. Boots automatically

I had this very similar issue a couple of years ago but I forgot how I went about resolving it.. a couple questions though:
What Windows are you running?

Have your tried booting in safe mode? You can access the option for safe mode by pressing the F8 key when the computer is just starting up (you can press it multiple times to be sure you'll reach the right screen if you're not sure when to do it)

When in safe mode try running a virus scan!


note; I'm at work and can't watch your video on FB

Vista/windows 7:
– click on start key + Pause/break key
– on left hand column, click on Advanced system settings
– enter administrator password if needed
– under startup and recovery click on settings
– under system failure, uncheck automatically restart

Usually if the computer doesn’t restart or get a blue screen when in safemode, it means that problem is software based not hardware. Once you do the steps above, and you get a BSOD, make sure to record the error you are getting. If in the error it gives you a file with a .sys extension, make sure to record it too. Post results here, or you can use a program such as the following to research/fix error:
Buescreenview:
http://www.nirsoft.net/utils/blue_screen_view.html
whocrashed:
http://www.resplendence.com/whocrashed
And finally, you could try running system file checker in safemode. Make sure to have your installation disc handy in case you needed. To do so, try the following:
– click on start
– type cmd in search box (if in xp, click on run and type cmd)
– highlight cmd entry in search results, highlight entry and right click on it
– select run as administrator
– when command prompt opens, type the following:
sfc /scannow
– let the scan run

(1) make sure your RAM is ok using memtest86
* If you have some Linux Live CD there should be a memtest86 boot option too.
(2) make sure everything is within save temperatures e.g. using HW Monitor
save values are around:
Processor < 70°C
GPU < 95°C
SYS/AUX/CPU < 50°C * sometimes readings are wrong (ridiculous high)
Hard Drive < 50°C
(3) if you recently installed some new hardware make sure all power cables are connected properly * In case of a new graphics card make sure your power supply is sufficient
If (1) shows an error try to re-seat the RAM by taking them out and putting them back in again. If this doesn’t help you will have to get new modules.
For (2) your shutdown and unplug your computer, clean out the fans, and next time you turn it on make sure all fans are working.
For (3) it could be one of those rare cases where the power supply is faulty or near death. But this is like the last last possibility.

I was just looking into this sort of problem and it seems to be associated with a hardware problem.

You should look into diagnosing what part it could be (if it's actually a hardware part). I found a thread with some tips on doing that here:

Why does my PC keep restarting itself?

I'll repost what I see is important from the posts there, the link is for context! (ps; I think you should check your memory first! run the memtest86 and try unplugging/plugging your memsticks in!)

(Oh and I remember what happened when I had this issue too, it was my motherboard that was bad!! I hope it's not as serious for you.)

Another post:

It restarts after the windows is loading screen. Can't even get to the desktop, and it's my friend pc that has this problem so i try to help him