Constant setting up

Usually this problem occurs if the Office installation goes corrupt, due to multiple versions of office installed in the machine.
Step 1: Remove Multiple/trial Versions of Office Suites:

1. Click Start, click Run, type control appwiz.cpl, and then press ENTER to open the Add or Remove Programs window.
2. Check for multiple/trial versions of Office & uninstall them.
 
If the problem still persists, go to the next steps.

Step2: Add the registry key
Registry disclaimer:
Modifying REGISTRY settings incorrectly can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting from the configuring of REGISTRY settings can be solved. Modifications of these settings are at your own risk.

1. Click on Start>Run
2. Copy and paste the below switch

reg add HKCU\Software\Microsoft\Office\12.0\Word\Options /v NoReReg /t REG_DWORD /d 1
reg add HKCU\Software\Microsoft\Office\12.0\excel\Options /v NoReReg /t REG_DWORD /d 1
reg add HKCU\Software\Microsoft\Office\12.0\Outlook\Options /v NoReReg /t REG_DWORD /d 1
reg add HKCU\Software\Microsoft\Office\12.0\Power Point\Options /v NoReReg /t REG_DWORD /d 1
reg add HKCU\Software\Microsoft\Office\12.0\Access\Options /v NoReReg /t REG_DWORD /d 1
reg add HKCU\Software\Microsoft\Office\12.0\Publisher\Options /v NoReReg /t REG_DWORD /d 1
reg add HKCU\Software\Microsoft\Office\12.0\Infopath\Options /v NoReReg /t REG_DWORD /d 1

Restart the computer and check for the issue
 
If the above steps fail, reinstall Office. For more information on how to remove office check the below website:
http://support.microsoft.com/kb/971179