Computer starts then closes systematically

 The Mad Scientist -
When i turned on my computer in work all seemed well i.e. it started up, i typed in my password, desktop appeared and then it switched itself off and started the whole process again and again and again..........................

It does have a anti virus programme and I am the only one who use the computer. At one point it sort of started up and gave me options i.e. start in safe mode, normal mode etc. i clicked on safe mode and was able to start a scan. the trouble was every file it scanned came up as not tested! I tried again in normal mode but it just switched off again.
I'd appreciate any assistance on this, thanks

1 reply

Once my computer switched in the middle of the night, by itself... I was freaked out!!!!! Naughty naughty naughty!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!