just asking so im 100% sure nothing will happen!!!!!!!
 

if i delete all of my tables in mySQL
will my posts and member get deleted?

Since your databse is your tables - yes.

im trying to reinstall them all. which tables to i avoid deleting to keep my posts and members?

Frankly I wouldn't delete any tables unless you know exactly what you are doing. When you restore your databse, it will overwrite all the tables with the information from the backup. If you only want to restore certain tables, then this can be very tricky and may break your db for good. That's because each table is not an entitity unto itself. There are dependencies among the tables.

i guess i have to do this the hard way........
edit all the templates and change php3 to php

do a search-replace