Since you are talking Access ADP and ASP web application:
1. Access ADP is merely front end app and IDE for SQL Server, and it is
desktop technology (forget data page, it is gone in Access2007 anyway), so
different from web app (ASP or ASP.NET), you cannot "convert" onw to the
other, unless "converting" means complete re-write.
2. ASP is old technology and different from ASP.NET. With Visual Studio Web
Express2005, you can only develop ASP.NET, not ASP.
3. Sql Server Express is a database server, ( SQL Server 2005), and can be
used with ASP, ASP.NET, Access APD (though, you cannot design table, view,
SP and UDF with Access2003 and older on SQL Server2005/Express, you need
upcomming Access2007 for that) and other apps...