Try checking your hard drive for errors. How to check a hard drive for errors -
http://support.microsoft.com/default.aspx/kb/315265 If tune up still hangs after running chkdsk please contact support. How to reach support -
http://social.microsoft.com/Forums/en-US/onecareinstallandactivate/thread/30400b52-7f26-4ba0-bc18-17e305329d90Jim
Microsoft MVP Consumer Security - Forum Moderator - Live One Care - Live Mesh - Microsoft Security Essentials