QS, W2K3, Sql Server 2K

I have installed QuickStart (framework v1.1) over W2K3 with SQL Server 2K SP4.
Wathever i do, ASP.Net and Winforms applications are not functionning. Sql Server can’t be reach by the applications. It says “can’t connect to Sql Server”.
I’m not on a PDC and without “Active directory” !
Anyone have an idea ? Wich accounts/users are used in each case (directly and by IIS) ?
I’m stuck since a long time now, so please help !