In my experience, a dead blu ray motor/lense, you can still run multiman and most games worked for me on 3.55 kmeaw.
with a dead blu ray logic board (no reply to disc function, no blue LED), no apps will launch, you cannot do firmware updates. only web browser, music/pic/videos work.
there is two options, one is to use the disk bypass recently released.
option 2 is to wait for remarry logic board that is still under development.
option 3 is to do the BGA swap
[ame=http://www.youtube.com/watch?v=6Zh46cR6k3s]YouTube - PS3 controller board BGA swap[/ame]