If you see CrExtP4z.exe, signed by Mindspark Interactive Network, running in the Task Manager you’ve probably installed a “Video Toolbar”.
Avast detects it as “Win32:Mindspark-A [PUP]”, KingSoft as “Win32.Troj.Undef.(kcloud)” and Vipre as “MyWebSearch.J (v) (not malicious)”.
Looking for removal instructions? Easy, just remove it from the Add/Remove programs dialog in the Window Control Panel.