Computer will not shut down

[Bobguyawesome]

Every time I shut down my computer it stays off for 3 seconds and boots right back up, I have had this problem since I built it. Here are the specs

i3 3220
MSI H61MU-E35 B3 (Mobo)
4gb 1600MHz ram
Bios is up to date.

Any response on helping me is much appreciated!

 

[johnb35]

What power supply do you have?

 

[Bobguyawesome]

Standard 300 watt from dell. Came with an Inspiron desktop.

 

[johnb35]

Replace it. Dells don't have standard power supplies.

 

[crux77]

There is also a setting in the bios that autostarts on system shutdown, might want to check that.