Uninstall Ask.com "services" and toolbar

Try ToolbarCop http://www.snapfiles.com/get/toolbarcop.html 
(very old solution: if that doesn't work, see below)

 Also useful as a diagnostic tool - FileHippo Download - HiJackThis and post the contents of the HJT log file here. - HJT Information HiJackThis Tutorial.
Download and run HJT and post the contents of the log file (cut and paste or attach the log file) into this topic, you may need to split it over two or more posts depending on how large it is.