Do not use IExplorer version<7! Better: uninstall it completely!
Use Firefox, Flock or Opera instead (with webpage-threat advisors as belarcAdvisor, Sitehound, wot and McAfeeSiteAdvisor)
Don't forget NoScript! And hosts related software to protect zonemapping
Use Spybot Searcha&Destroy!
supposed to be a windows system file
This hijacker pretends to belong to the windows system files. It runs in background, hijacks the start pages of the Internet Explorer and adds itself as debugger for exe files to get started with every application. Bestsearch.Scvhost also adds itself twice to the system start.