OK next bit is rather tedious..
What we will do is run just windows files and services
Then add the other files/services one at a time to determine which is causing the problem
Step 1: Start the System Configuration Utility
1.Click Start, click Run, type msconfig, and then click OK.
2.The System Configuration Utility dialog box is displayed.
Step 2: Configure selective startup options
1.In the System Configuration Utility dialog box, click the General tab, and then click Selective Startup.
2.Click to clear the Process SYSTEM.INI File check box.
3.Click to clear the Process WIN.INI File check box.
4.Click to clear the Load Startup Items check box. Verify that Load System Services and Use Original BOOT.INI are checked.
5.Click the Services tab.
6.Click to select the Hide All Microsoft Services check box.
7.Click Disable All, and then click OK.
8.When you are prompted, click Restart to restart the computer.
Step 3: Log on to Windows
1.If you are prompted, log on to Windows.
2.When you receive the following message, click to select the Don't show this message or launch the System Configuration Utility when Windows start check box, and then click OK.
You have used the System Configuration Utility to make changes to the way Windows starts.
The System Configuration Utility is currently in Diagnostic or Selective Startup mode, causing this message to be displayed and the utility to run every time Windows starts.
Now shut the computer down, if it shuts down as expected then reboot
Run MSConfig again and enable half of the services
Does it still shut down properly, if yes then re-enable half the remaining services until the problem re-appears
Once it has reappeared disable all bar one of the last services restarted and then check each service to determine which one is stopping the shutdown
To return to normal boot
Steps to configure Windows to use a Normal startup state
After you used the clean boot to resolve your problem, you can follow these steps to configure Windows XP to start normally.
1.Click Start, and then click Run.
2.Type msconfig, and then click OK.
The System Configuration Utility dialog box is displayed.
3.Click the General tab, click Normal Startup - load all device drivers and services, and then click OK.
4.When you are prompted, click Restart to restart the computer.