What happens if index.dat files are deleted?

Answer 1

Improved Answer

Actually index.dat files are used by internet Explorer to keep your history and other information organized. Deleting them will not do anything to harm your computer and most cleaning software will delete these files, which will allow your computer to preform faster.

Since index.dat files are actually just files and has nothing to do with hardware, you have nothing to worry about when deleting them. Just make sure you have a reason for doing so. As stated above, Internet Explorer does use them for pulling information.

Original Answer

the programs that would use them will not run anymore. sometimes it will crash your computer (blue screan) or burn out a peace of hardware (hard drive, ram)