Windows XP Clients & Server 2003 hang when at last stage shutting down

Firstly, I put this under XP category cause there was not one for Windows Server series. XP is what it is built off so that's why its here. Anyway, onwards with my problem:

I've been having a problem with my Windows 2003 domain lately. Every time i go to shut down the server and the clients, Windows hangs at the blue (XP) or silver (2003) screen with only the cursor. Results vary from computer to computer, like my network has 5 computers: My desktop, my second desktop (old parts), my laptop, my dad's desktop and the server. My desktop bluescreens after 20 mins of the start of the hang and restarts, too fast to see what its about. My laptop hangs for 5 minutes, my desktop 2 for 5 minutes and my dad's about 7 mins. The server is the worst. it WON'T turn off. it just sits! Why am I having this problem? its definatly the domain cause when i set up new clients with fresh Windows XP Professional x86 or x64 they are ok on WORKGROUP but when I add them to the domain GLADWELLS they hang. Very strange!? Can anyone here figure out whats going on? I'm stumped trying to work it out.

Thankyou,
dglad4.