Authentication in SQL Server

Hi folks,

Got a massive problem.
I'm starting to develop a new website using ASP.NET v3.5 (the CTP of Microsoft's new Visual Web Developer "Orcas"). I saved the project onto a network drive (called X: for the purposes of this discussion) - X:\Orcas_WS\VVProject.
Set up a new database and table to upload files from an ASP.NET AJAX form to a database table, fields as follows:
[ImgID] - type int, Identity field, auto-increment of 1;
[GallID] - type int;
[GallPos] - type int;
[ImgContentType] - type nchar(10);
[ImgContent] - type image (binary data);

Worked a dream when running the development server on my laptop and using my own username and password to upload stuff to (in connection string, using Integrated Security = SSPI).
Have now uploaded this to a live server, installed .NET Framework v3.5 on my server, (attempted to) enable IUSR_MACHINE account to have read/write access to my DB and now it's all gone to pot. None of my accounts can authenticate against this DB using .NET - whether it's NETWORK SERVICE, or IUSR_CM-SUMM, even my own username and password, with Integrated Security both set to SSPI and False.
I am now getting intermittent errors where login will either succeed but .NET will try and use named pipes and says "there is nothing on the other end of the pipe" with an event 3005 in my event log, or I get an "login failed for user (username)" message and a failure audit in my event log.

I read up somewhere about having to deregister the Service Principal Name to avoid auth errors (which is what seems to be happening), but having trawled Microsoft's website for hours, there seems to be no documentation or instruction on how to deregister an SPN.

Please help folks, this project is financially lucrative and I want to make a fantastic impression on the client with a low development time overhead!

Many thanks in advance,

medicineworkerAdmin, please close thread, problem sorted - my MS SQL Server was being stoopid, my schema permissions had (rather strangely) been entirely wiped out... lol, have fixed.

Cheers!