You should update Hijackthis to the latest version (1.98.2); it may find something new. There's an update feature in hijackthis, or you can get it here:
http://www.softpedia.com/progDownload/x-Download-5034.html
CTHELPER.EXE is not really needed; it's not harmful but does use some system resources. You can get more info on it here:
http://www.liutilities.com/products/wintaskspro/processlibrary/cthelper/
You can find information on many processes and recommended settings here:
http://www.blackviper.com/WinXP/servicecfg.htm
and more info here:
http://www.liutilities.com/products/wintaskspro/processlibrary/
There's a link to a Hijackthis tutorial in this thread if your interested:
http://www.daniweb.com/techtalkforums/thread5690.html
After you update HJT, close all browser windows, scan with HJT, and post a new log.