Error 1601 Main Repair Option
1. Power on your computer, and wait for your computer to boot up. Click the 'Start' menu icon in the lower left corner of the screen. Click 'Run.'
2. Type 'msiexec /unreg' into the 'Run' dialog box without quotation marks. Click the 'OK' button to continue.

3. Click the 'Start' button. Then click 'Run' again. Type 'msiexec /regserver' with quotation marks. Click the 'OK' button, and then restart your computer.
Error 1601 Secondary Repair Option
4. Click the 'Start' menu icon. Go go 'Programs,' and click 'Accessories.' Select the 'Command Prompt' program in the drop-down menu.
5. Type 'msiexec /unregister' with quotations into the Command Prompt application, and press the 'Enter' key.
6. Type 'msiexec /unregister' again without quotations into the Command Prompt window, and press the 'Enter' key. Close the Command Prompt window.