Do you have a Windows IIS or Apache web server ?
Details of the web design software you have available and are comfortable using.
Do you have dynamic language and database support from your web host ?
If you have database support from your host, how many databases are you allowed and if you are limited to one is it currently being used for something ?
The level of traffic you expect the user management system to handle (this goes a long way to deciding how well your host/database will cope)