iMac Early 2008 6gb ram won't boot

[jaywongy]

I ordered a 4gb+2gb kit and installed it to my computer, it seemed to run fine until I shut the computer down for the night and then booted it back up, the computer now beeps after I switch it on. I tried running it with just the 2gb stick in and it seems to boot up fine. I am running Mountain Lion so could this be why?

 

[miles01110]

Did you try with just the 4 GB stick? Maybe it's bad.

 

[jaywongy]

Just booted it with the 4gb stick only and it booted okay, i then put the 2gb back in with it and i get the same beeping problem