Hello. I recently opened up my iMac 13,1 21.5" late 2012 to upgrade the ram as well as exchange the HHD with SSD. When I put everything back together and try to boot up all I hear is the chime but the display does not turn on. Any suggestions before I open it up again? Thanks.

Update: I took the iMac to a Mac repair shop here in Austin. They said I most likely shorted out the logic board installing the new ram. Apparently iMacs don't like being upgraded. The shop won't even upgrade the ram because of this. So now I sit here with a dead computer, an SSD, and new ram that are totally worthless. Thanks OWC!