1. Download the missing comctl32.dll file. Locate a website that offers the comctl32.dll file. You can also use the link in the Resources section.
2. Unzip the download file if it is a .zip-type file. Right-click on the file and choose 'extract' to make the file available in a .dll format.

3. Install the missing comctl32.dll file in the proper folder on the computer. If the operating system is 64-bit Windows, copy comctl32.dll to the 'C:\Windows\SysWOW64' folder. If the operating system is 32-bit Windows, copy comctl32.dll to the 'C:\Windows\System32' folder.
4. Restart the computer by clicking on the 'Start' button and selecting the 'Restart Computer' option.
5. Open the computer program that previously displayed the error message stating that the file comctl32.dll was missing. This will verify the program now works properly.