Pc will only power up when pwr2 pin is removed

Hello, I bought new case for my pc because the old was was looking tatty. I removed everything and put it in the new case exactly how it was in the old one, however it will not power up - it will flash then nothing. I tried a few things and after trial and error i noticed that the pc fan etc. will only power up when PWR2 pin is removed, and when i plug it back in, nothing. What could be the problem? All I wanted was a new case and now I dont have a working pc lol

Thanks

I forgot to add that I have tried another power supply and the same thing is happening

Thanks

did you use stand offs behind the mobo?

Does the new case use stamped motherboard tray standoffs or individual brass or steel screw post standoffs?

By your problem description there seems to be a short circuit occurring.

thanks everyone... problem solved.... I feel so stupid now I completely forgot to screw the new standoffs in! Everythings working fine now and Ive gave myself a slap on the wrist for making such a silly mistake

Thanks again!