When you use the windows library update download (SPEU.exe) you are not actually replacing the dll file, because you cannot replace a file that is in use. Windows uses MFC42.dll when it is running, therefore you must go into DOS mode to install it properly.
Step 1 - go to the following site and download mfc42.dll version 6.00.8665.0
http://users3.ev1.net/~srudenko/dll/mfc42.dll
save the file to C:\ drive (not in a folder. This just makes it easier)
Step 2 - Restart in DOS mode
Step 3 - At the prompt (C:\) type the following:
copy mfc42.dll C:\windows\system
You will get a message that is asking if you want to overwrite the existing version of the MFC42.dll file. Hit Y for yes. You have now installed the updated version of MFC42.dll.
Step 4 - At the prompt (C:\) type exit. This will restart windows.
Double click on your K-Meleon Icon. It should work now.