C:windows\system32\rundll32.exe application not found

If I try to open anything in control panel I get an error saying C:windows\system32\rundll32.exe application not found.

Backup your data and reformat your pc its screwed.

how do you reformat your pc? If I can not remove any programs throught the control panel , how do I get the old programs off the computer?

The Currently installed programs list in the Add or Remove Programs tool lists all of the Windows-compatible programs that have an uninstall program or feature. Occasionally, a program may not be removed completely, and the registry key that is used to display the program in the Currently installed programs list remains. In this situation, you may need to manually remove the program from the Currently installed programs list in Add or Remove Programs. To do this, follow these steps.

1. Click Start, and then click Run.
2. In the Open box, type regedt32, and then click OK.
3. In Registry Editor, locate the following registry key:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
4. In the left pane, click the Uninstall registry key, and then click Export on the File menu.
5. In the Export Registry File dialog box that appears, click Desktop in the Save in list, type uninstall in the File name box, and then click Save.
6. Each key listed under Uninstall in the left pane of Registry Editor represents a program that is displayed in the Currently installed programs list of the Add or Remove Programs tool.
7. After you identify the registry key that represents the program that you removed but which is still displayed in the Currently installed programs list of Add or Remove Programs, right-click the key in the left pane of the Registry Editor window, and then click Delete. Click Yes in response to the "Are you sure you want to delete this key and all of its subkeys?" message.
8. On the File menu, click Exit to quit Registry Editor.
9. Click Start, click Control Panel, and then click Add or Remove Programs. In the Currently installed programs list, verify that the program whose registry key you deleted is no longer listed.