If you don't changed anything, probably it's a hardware problem. Change your mouse. If not a hardware fail, or you change some settings accidentally, or is a virus.
If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem. Also please exercise your best judgment when posting in the forums--revealing personal information such as your e-mail address, telephone number, and address is not recommended.
Single Click is Double-Clicking instead
I can hardly get any work done, as it does this in every application I am in and is driving me insane! Please help!