Changes to software (programs) and hardware (equipment) can sometimes cause software problems, such as:
1) Conflicts with other software: Newly installed software may conflict with other software. For example, Symantec Norton Antivirus can conflict with competing antivirus products. So, if you recently installed another antivirus program and Norton Antivirus no longer works correctly, uninstalling the other antivirus product could solve your problem.
2) Changes to computer settings: Undo any recent changes to your computer's settings, and try launching the software again. For example, the Windows Control Panel includes an option to "Set Program Access and Defaults," which allows you to disable access to certain applications. If you accidentally disable access to a program here, the program may not run.
3) Conflicts with new or improperly configured hardware, such as scanners and printers. If you've recently connected new hardware to one of your computers, try disconnecting the hardware and see if that corrects the software issue.
https://www.techsoup.org/support/articles-and-how-tos/eleven-tips-for-troubleshooting-software