1. A few months ago I downloaded some freeware. The freeware had malware that caused some immediate problems (locked up my browser (Firefox) and redirected my home page.
2. I deleted the freeware and fixed my browser.
3. I am left with an annoying error (Windows cannot find 'C:\Program Files (x86)\user extensions\client.exe. Make sure you typed the name correctly then try again'. See attached screenshot. The error pops up every time I boot my PC. I can close it by clicking 'OK' on the error message. The error continues to pop up at what seems to be random intervals when I am using the PC. The error doesn't seem to be causing any performance problems. It's just annoying.
4. I have searched my hard drive and registry for the string .... client.exe, downloaded installed and run the Autoruns tool. So far I have not been able to find and delete the source of the error.