It's possible that the "Quick Launch" folder was deleted, and needs to recreated. Check to see if the "Quick Launch" folder resides at the following location: C:\Documents and Settings\"Your account name"\Application Data\Microsoft\Internet Explorer
...if not, create a folder named "Quick Launch" under the above directory tree. Then under the "Directory" tab in "Taskbar and Start menu properties", make sure "Show Quick Launch" is checked under "Taskbar Appearance".
If the above checks out OK, give this a try...Start | Run | Type regedit and click OK | Expand the following branch...
HKEY_CURRENT_USER | Software | Microsoft | Windows | CurrentVersion | Policies | Explorer
With the Explorer Key highlighted, right click in the RH pane and select 'New-->DWORD Value' | Give the new DWORD the following name...
NoSaveSettings
...with a value of 0 (right click the DWORD you just created and select 'Modify' | In the 'Edit DWORD Value' window that opens, make sure that in the 'Value data' field...0 is shown as the value).