I'm troubled with ask search toolbar, it is difficult to get rid of it, i also ask this for help, someone give me a removal guide link, https://www.virus-delete.com/en/guides/browser-hijacker-removal/20130814-how-to-remove-ask-search-toolbar-through-isafe-virus-removal-tool.html
it's But it requires to download sth, so can someone know whether it is reliable? , and my OS is windows 7, Please help!

You should not have to download anything to remove the optional Ask toolbar that comes with the ClamWin download. It is not malware. Use the Control Panel, Programs and Features, click on the Ask Toolbar listing, and choose to uninstall the program. That should remove it without any problem.

Regards,