If you have downloaded the file from this site it will be in a zipped format, you will need WinZip to open the file.
First unzip the file by double clicking the downloaded ZIP file.
Extract it to an empty folder or create a folder (c:\temp) to store it in.
NOTE: Most files cannot be replaced in windows (since windows may have the file open and in use).
Try it first and see if you can install it using the Windows method:
Locate the file with the Find tool, usually the files are located in the windows\system folder.
In the found results window right click on the file and select Rename and change the extension (.dll) to .old you will get an error if the file is open in windows stating that it cannot be renamed, and you will have to replace it in DOS (see DOS section).
Then copy the new (unzipped) file to the same location (windows\system), if you get an error:
"File Exists" don't over write the file, go to the Find tool and rename the file to "filename.old", you will want to you want to do this so if the new file does not work you will have a way to get the old one back (rename the .old file to .dll).
How do I install a DLL File from DOS?
First, unzip the file to a folder called c:\temp in windows.
Then, locate and remember the path to the existing file (normally windows\system)
Reboot the machine to a true DOS prompt to replace the file, Restart the Machine, watch for the Starting Windows prompt and press the F8 key select Command Prompt only.
Change to the folder where the file is stored ("CD C:\Windows\System" then press enter) and rename the existing file (ren filename.dll filename.old (press enter) where "filename" is the name of the dll file in question)
Next, change to the temp folder ("CD C:\temp" and enter) and then copy the file to the folder where the file you are replacing is located ("copy filename.dll c:\windows\system, enter")
Reboot the system and see if the application works.