Best free Antivirus is AVG Free, totally Free
http://free.grisoft.com/doc/2/
As mentioned by Irish, Spybot Search & Destory is the best for removing spyware.
An excellent and Free tech support site that will help anyone with anything computer related, FREE. They can recommend the best of everything..you can search on there about how to be secure and if you have spyware or adware I suggest:
Click here to download HJTsetup.exe:
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http://www.thespykiller.co.uk/files/HJTSetup.exe
Save HJTsetup.exe to your desktop.
Double click on the HJTsetup.exe icon on your desktop.
By default it will install to C:\Program Files\Hijack This.
Continue to click Next in the setup dialogue boxes until you get to the Select Addition Tasks dialogue.
Put a check by Create a desktop icon then click Next again.
Continue to follow the rest of the prompts from there.
At the final dialogue box click Finish and it will launch Hijack This.
Click on the Do a system scan and save a log file button. It will scan and then ask you to save the log.
Click Save to save the log file and then the log will open in notepad.
Click on "Edit > Select All" then click on "Edit > Copy" to copy the entire contents of the log.
DO NOT have Hijack This fix anything yet. Most of what it finds will be harmless or even required.
Then go to the below site, register (free) and go to the security forum and post your log, they will instruct you on how to get all the yuck off...sometimes the scans dont' get it all!
www.techsupportguy.org