Running the optimizer will not restore the server. There are many settings that are not contained in any of the edb's. I suggest you view
http://support.microsoft.com/servicedesks/webcasts/wc091699/wcblurb091699.asp?LN=EN-US&SD=gn&FR=0&qry=disaster%20recovery&rnk=1&src=DHCS_MSPSS_gn_SRCH&SPR=ECH
for a webcast and presentation of disaster recovery for exchange.
There are also numerous books on recovering from an exchange disaster. I suggest you quickly start reading or call in a professional. There are many things you must do to bring that server back to it's pre-crash functionality. Having been through a major crash and corrupt database recovery, I cannot stress enough how important it is to have the right help from the beginning.
GOOD LUCK - Microsoft Exchange Support Services are fantastic at helping in this situation. At the current price of the call, it is WELL worth it.