Why Does My PlayStation 3 Go To A Black Screen When Starting An App?

First, I change the laser by following the guide here on iFixit. Unfortunately, changing the laser didn't fix my problem. I come across a forum post suggesting restoring the file system might fix the (original) problem of the console not reading discs. I thought I'd try it since I figured there was nothing left to lose. Well, it turns out I had a lot more to lose as now my console will not launch an app or game but instead it stays on a black screen.

I've tried reformatting the hard drive, and then rebuilding the database and restoring the file system again to no avail. I haven't found anything helpful on Google other than perhaps a failing hard drive? Could I have done something wrong when I changed the laser? Perhaps my hard drive happened to die at the worst moment? Any one else have any ideas?

Thank you for your help,

~Brett