iTunes won't open.

At first iTunes wouldn't sync purchases that I'd made on my iPad so that I could put them on my iPod too, so I tried to update it thinking that was the problem. Then instead of updating, it comes up with the message "The program can't start because api-ms-win-crt-heap-|1-1-0.dll is missing from your computer. Try reinstalling the program to fix this problem." I have uninstalled it and reinstalled it several times, but it still pops up with the error and won't open. What can I do to actually make iTunes work?? Operating system is Windows 8. Please help!!