How to Fix a Bad Image Checksum

1. Insert a clean Microsoft Windows Millennium Edition (ME) or Microsoft Windows 98 Edition startup disk into the computer, and hold the reset button on the front of the computer until the system commences rebooting.
2. Navigate the Windows startup menu with the keyboard's directional keys and select 'Start Computer with CD-ROM Support'. Hit 'Enter' to continue.
3. Write down your CD-ROM's drive letter on a piece of paper.
4. At the command prompt, type 'Drive:' without quotes (Drive should be replaced with the drive letter on which Windows is installed), and press 'Enter.' Type 'cd windows\system32' without quotes, and press 'Enter.' Type 'ren user32.dll user32.old' without quotes and again press 'Enter.' This renames your damaged user32.dll file so it is not recognized by the system, but still physically exists as a backup if needed in the future.
5. Eject the Windows ME or 98 disk, and insert the Windows XP disk.
6. At the command prompt, type 'extract CDROMDrive:\i386\user32.dl_ Drive:\windows\system32\user32.dll' without quotes, replacing CDROMDrive with the CD-ROM's drive letter that you made a note of earlier, and replacing Drive with the system's drive letter on which Windows is installed. Hit 'Enter' to execute the command. This process extracts a new copy of the user32.dll file to your hard disk, from the Windows XP CD. The new file will be found in the Windows/System32 directory.
7. Restart the system by holding the reset button on the front of the tower until reboot commences.