You should use an antivirus program and antispyware software, if your computer is now infected with viruses and/or spyware.
Here you have more information on computer security, as well as excellent and free programs that you can download into your computer:
The website list top ten the best and newest anti-spyware in 2009.
http://toptenantispyware.com
All are safe and can be trusted and you can download one.

SpyBot: http://download.cnet.com/Spybot-Search-amp-End/3000-8022_4-10122137.html

or,

Malwarebytes: http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html

or,

AdAware: http://download.cnet.com/Ad-Aware-SE-Personal-Journal/3405-8022-5153545.html

Error Fix – Safely Scans, Cleans, and Repairs you PC of any Errors that cause pc slowness!

Try Avast,malwarebytes,adaware,superantispyware.If those don’t find anything,go to someone who is excellent at computers and clean your PC.

Follow the instructions in the link not more than and a trained analyst will give you help removing any infections that you have for free and give you advice on staying safe in the prospect.
http://www.tnthelpforum.com/viewtopic.php?f=60&t=834

You need to scan with a excellent antivirus program to remove adware and other malicious programs. Have a look at http://www.datadefender.net for reviews and download links for the latest software from the major antivirus companies. This will clear up any adware, spyware, viruses, trojans, worms and so on as well as protecting you from any more.