How to Restore Rundll32.exe Without an Installation Disk

Run System Restore in Normal Mode
1. Log on to your computer as an administrator.
2. Close any open files and save your data in any open programs.
3. Open 'System Restore' by clicking 'Start' and then typing 'System Restore' (without the quotes) into the search box above the Windows icon or Start button. Click 'System Restore' in the list of options provided. Click 'OK' if prompted, then click 'Next' in the 'System Restore' application window.
4. Select a restore point from the list provided. Windows periodically creates 'restore points' that record your computer' s programs, hardware and registry setting. Choose a date before the day on which you started having problems with rundll23.exe.
5. Click 'Next,' then click 'Finish' to begin System Restore. Windows will automatically restart your computer in order to return it to the restore point you selected in Step 4.
Run System Restore in Safe Mode
6. Boot your computer in 'Safe Mode' by restarting it and holding the 'F8' key as the computer reboots.
7. Open the command prompt by clicking 'Start,' then typing 'cmd' (without quotes) into the search box.
8. Type 'rstrui.exe' (without the quotes) into the command prompt, then press the 'Enter' key. Click 'OK' if prompted. Click 'Next' to proceed to the 'Select Restore Point' panel.
9. Select a restore point from the list provided. Choose a point whose date falls before the day on which you started having problems related to rundll32.exe.
10. Click 'Next,' then click 'Finish' to begin the System Restore process. System Restore will restore your operating system to the earlier configuration.