Will not let me install or uninstall programs after installing service pack 2.

try uninstalling sp2 and then try installing if this dosent work you would need to do a repair install or clean install on your xp

Uninstalling SP2
This service pack contains an uninstall mechanism that you can use to restore your computer to its previous state. When you run W2ksp2.exe to install SP2, a subfolder named $NTServicepackUninstall$ is automatically created in your systemroot folder. To turn off this W2ksp2.exe option, see the Install SP2 earlier in this artlcle.

Important:

• If you install any programs or services that require SP2 or that have fixes contained in SP2, uninstalling SP2 could adversely affect those programs.
 
• If you turn off the automatic backup option for W2ksp2.exe, you cannot use the uninstall SP2 mechanism and, therefore, cannot uninstall the service pack.
 

Using Add/Remove Programs to Uninstall SP2
You can uninstall SP2 by using Add/Remove Programs in Control Panel.

To uninstall SP2 by using Add/Remove Programs:

1.
 Click Start, point to Settings, and then click Control Panel.
 
2.
 Double-click Add/Remove Programs, click Windows 2000 Service Pack 2, and then click Change/Remove.
 
3.
 Follow the instructions that appear.
 

Using the Uninstall Program to Uninstall SP2
You can uninstall SP2 by running the uninstall program from the command prompt.

To uninstall SP2:

1.
 Click Start, and then click Run.
 
2.
 In the Open box, type cmd, and then click OK.
 
3.
 Type cd %systemroot%\$NtServicePackUninstall$\spuninst\, and then press ENTER.
 
4.
 Type spuninst.exe, and then press ENTER.
 
5.
 To close the Command Prompt window, type exit.
 

I only have this problem when i install service pack 2.

I do not have any problem before.