many thanks for the detail answer

--- one last Q --

how about , clustering and (or network load balancing in the windows 2003 server itself)

and

adding one more server computer, and using Master/ Target features of SQL server 2005

for the above methods

will there be any thread in SQLserverCentral.com that would tell us- about the precaution (or procedures) during such upgrade

=== for the CRASH that I mentioned earlier, is it the mistake that I try to upgrade with the same instance name -- during new installation===

thanks for all your guidance