If you get an error stating that MSVR80.dll is missing when you try to run iTunes or even when you start your pc go to My Computer and then selecting Uninstall or change a program. Let the list of programs load and then select Apple Application Support. Click uninstall. Once it has uninstalled click on the start menu and using the search box find Apple Software Update. Run this program and update iTunes. It may require a restart after it updates. This should fix your problem. Apple Application Support will be reinstalled, but will be working properly now.
MSCR80.dll is associated with the Apple Application Support program. This error can be caused sometimes if you go to update iTunes and it glitches and errors out. I'll update this post with other causes and solutions for this error as I find them. This particular solution worked out for me because my iTunes update had glitched a few days prior.
