If you ever are in the situation that your ePO 4.5 server crashed and you need to reinstall it check it this procedure for getting it started and running again:
http://www.jackcobben.nl/?page_id=233
NOTE: If you don’t follow these steps then you arein trouble. Make sure you have the same server name and same database instance name (EPOSERVER). Otherwise you can reinstall SQL again to get it working !!!!!