Click Start, Run and type regsvr32 /i shell32.dll and press Enter. It will take awhile and then click OK.
Restart the PC and see if they show up.
Check to see if these settings have been modified, they should be the same as the instructions below.
Open the Registry Editor by clicking Start, Run and type regedt32 and press Enter.
Navigate to HKEY_LOCAL_MACHINE\ SOFTWARE\ Microsoft\ Windows\ CurrentVersion\ explorer\ Shell Folders and make sure all the entries here point where they should:
In Windows XP/2000/2003, the Common Startup value should be set to C:\Documents & Settings\All Users\Start Menu\Programs\Startup.
Navigate to HKEY_CURRENT_USER\ SOFTWARE\ Microsoft\ Windows\ CurrentVersion\ explorer\ User Shell Folders and correct the values here as well. The only difference here is that each entry should start with %USERPROFILE% instead of C:\Users\{your_user_name}.
When you're done, close the Registry Editor and restart Windows to test the new settings.
If those settings are OK then create a new User Account and see if it will work. If it does it will mean that the Profile has became corrupt.
How to copy data from a corrupted user profile to a new profile in Windows XP
http://support.microsoft.com/kb/811151
The other alternative is to copy the links to your profile.
Right click start, select Explore All Users this opens the "Documents & Settings" folder where all this information is stored.
Keep us informed as to your progress if you require further assistance.
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