HELP! I replaced my PSU and now it just shuts off and on again!

[Landocommando321]

I just upgraded from a 400w SolyTech (cheap PSU) to a brand-spanking-new 520w Seasonic S12II. I tried powering it on and it turns immediately off again and then turns on again infinitely unless I turn it off. Did I accidentally disconnect a cable in the process? What could be wrong?

 

[maxwellmelon]

start with basics

where you having any issues before you upgraded?

are you sure all the cables are pluged in good? are you sure you pluged in the cpu power connector and such?