Recently I purchased a Rosewill Fortress 450 to put into my HTPC/file servers build for better efficiency (old PSU is still functional). The problem is that after installing I can't even get it to POST (fans start up, so does HDDs but nothing coming up on my screen). I checked to see if my old PSU still runs it which is does, and tested the new PSU in my gaming rig and it works on there. Any ideas?
AMD Phenom X4 9600
(Old PSU was taken off of an old HP desktop)