Server 2008 Enterprise x86 AD GPO Help?

Hello all,

Firstly, I posted this thread here because networking was its closest related category other than Vista for Server 2008. So onto my problem..

Well I had just (about 5 hours ago) installed Microsoft Windows Server 2008 Enterprise SP1 trial I download from Microsoft directly. So I installed the full installaltion and configured it and blah blah like you have to with fresh Windows.

I finally got onto starting up the role for Active Directory Domain Services and created a new domain in a new forest and got the wizard to configure DNS to work with it too. I created my Organizational Units and added my computers and added new users with roaming profiles. It had all worked perfectly and I have been playing around with settings in the GPO for the OUs. This has only just happened but for a group of standard users, when they log on to an XP client, all access to network folders are denied! I had specifically changed permissions for the user to access the folder with full control, changed ownership to the Administrators security group, turned off inheriting permissions and also tried deleting all of my GPOs set for the domain. STILL, no fix.

Can anyone tell me what the hell is going on and how to fix it??
This server is set up in my home just to play around with so if I can get this fixed I will know for future purposes.
Please suggest as many things as you can because I REALLY don't want to have to re-format

All help is greatly appreciated,

dglad4.