Hi, and welcome to Justanswer. My name is ***** ***** i will be assisting you today.
To get started, I need to know what type of computer you are using, a Windows XP, Vista, Windows 7, Windows 8, Windows 10 or a Mac.
If its a Mac, please check the OSX version as follows, Click the apple sign at the top left of your screen, then click about this mac. And then where it says version, send that to me as a reply.
Do you mean it disappeared from your desktop?
Can you find it in your programs?
Please go to control panel, select programs and features
and then look through your list there for System Mechanic.
Is it listed there? Or 'missing' as well?