Why does my power light never turn on?

My PS3 was working fine, then my roommate inserted a movie disc and once it was inside, my PS3 powered down. Now the power light doesn't show that the PS3 is getting power. Could this be a problem with the disc drive or is this totally a power supply problem? I've tried to Google Search my problem, but it seems too uncommon.

Once I know the answer, then I know what I should fix.