If you are experiencing any installation issues, check your Windows Event Logs (application log, specifically) as you'll usually find the answer in there.
For example, if you see any PostgreSQL issues, search the forums for any references and you should find some answers.
Also check the prerequisites prior to performing the installation - as a bare minimum, you'll need .Net 2.0 SP2 and IIS installed (unless you are planning to use the Cassini web server instead)