|What browser, what operating system?|
You said you "deleted everything" you could find. Deleting doesn't work. You need to uninstall. Go to Control Panel and either Add/Remove Programs (in XP) or Programs-Uninstall a Program (In Windows 7).
Find the entry for 'mywebsearch' and choose uninstall.
You should also go to the "Add-Ons' tab for your browser and "Remove" the toolbar there.
If this doesn't work, let me know what browser you're using.