My computer which usually switches on isn't switching on

[Ricochet J]

Hi

I had to relocate my computer from London to Suffolk. When I set the computer up again it just doesn't start up!

The PSU lights switch on, the motherboard lights switch on but when I press the button on the case it just doesn't switch on!

I thought maybe it was a loose wire from the on/off switch but I know that's not it because when I press the manual on/off button on the motherboard it still doesn't power up!

Any help would be great!

 

[Ricochet J]

Well sometimes what happens when I press the on/off button is the computer powers up for half a second then switches off!