HELP me get rid of BACKWEB SECURITY NOTICE???!!!............?

I have this notice on forefront of screen for weeks...tried numerous anti-spyware/anti-virus etc...see list! I've also learned that it may be more harmful to outright remove it from computer! I don't even know where to start that process anyway (first touched a computer 9mos ago!) I have a HP Compaq with Windows XP which I bought almost a year ago. Does anyone have any other advice or solutions?---will need easy to follow /specific instructions ...Spybots search and Destroy http://www.download.com/3000-8022-101221...

adaware se%26gt; http://www.download.com/ad-aware-se-pers...

http://www.webroot.com/land/freescan.php...

a-squared Free%26gt; http://www.emsisoft.com/en/software/free...

http://housecall.antivirus.com/housecall...

http://housecall65.trendmicro.com/...

X -Cleaner Micro Edition scan http://www.spywareguide.com/onlinescan.p...

http://www.kaspersky.com/virusscanner...

http://www.windowsecurity.com/trojanscan...

http://www.bitdefender.com/scan8/ie.html...

http://www.pandasoftware.com/products/ac...

http://www3.ca.com/securityadvisor/virus...

http://www.javacoolsoftware.com/spywareb...

Spywareguard too.

http://www.javacoolsoftware.com/spywareg...

http://www.ewido.net/en/onlinescan/...

Get free anti virus for free click here.

http://free.grisoft.com/doc/1

http://avast.com

HELP me get rid of BACKWEB SECURITY NOTICE???!!!............?norton