What is it?

gcASCleaner.exe is part of the Giant / Microsoft Antispyware application.

What does it do?

Giant microsoft antispyware is a security technology that helps protect Windows users from spyware and other potentially unwanted software.

More info:

[url=http://www.microsoft.com/athome/security/spyware/software/about.mspx]microsoft.com[/url]