I was going to hex edit an *.exe-file and I accidentally associated all *.exes to open up in the hex-editor. Now I can't start any applications in that user profile. I know I could do a system restore or just backup the files and delete the account to solve the problem but that would cause some extra work. How can I undo the association? (registry edit? where?) I'm running Windows 7 Ultimate. BTW, how come this is even possible? This little accident disabled my antivirus software (for that account only, after re-start) and it never asked the administrator permission to do that. Isn't that a possible vulnerability?