Detailed fix for Windows Server 2003:
1. Go to Control Panel.
2. Double click "Add or Remove Programs".
3. Click "Add/Remove Windows Components".
4. Highlight "Application Server" and click "Details...".
5. Highlight "Internet Information Services (IIS)" and click "Details...".
6. Scroll down and highlight "World Wide Web Service" and click "Details...".
7. If Active Server Pages (ASP) is already ticked - untick it. (Same applys to Server Side Includes (SSI) if you are having the same problem with it). If it's already unticked then go to step 11.
8. Press "OK" on all the open windows that have "OK" on them then press "Next".
9. Wait for the wizard to finish making the new changes.
10. Repeat steps 3, 4, 5 and 6.
11. Tick Active Server Pages (ASP) and Server Side Includes (SSI) (Only if you are having the same problem with SSI as you are with ASP).
12. Press "OK" on all the open windows that have "OK" on them then press "Next".
13. Wait for the wizard to finish making the new changes.
14. Shut the Add or Remove Programs window.
15. Double click on the Plesk Control Panel icon in the task bar (Bottom right hand corner of the screen - next to the clock).
16. Press "Select All" then "Restart". Wait for it to finish restarting all the services and your done!
Hope this helps out others

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