Unable to access files.

My computer was running fine until around 3 PM today when all of I sudden it wouldn't access any files, giving me the message of "This file does not have a program associated with it for performing this action. Create an association in the Folder Options control panel". It's doing this with every single file I have and I've tried running my computer in safe mode and I still get the same message. So, if someone could help, it'd be greatly appreciated because I'm at a loss. Antivirus software and spyware software won't work either.