You haven't said which version of Windows you use. Anyway, check out
this link:
http://avscan.blogspot.com

Should help you decide.

See this link for info on dealing with malware:

http://www.elephantboycomputers.com/page2.html#Viruses_Malware

I'll recommend using Kaspersky Insternet Security.
It has the finest protection against
viruses,malware,spyware,scripts,dailers,banners.
I have tested all. Mcafee, trend micro, bit defender, pc cillin, Norton
[yukhhh], AVG, but nothings as affective as KIS.
I'll highly recommend you using it. I bet, it'll be the last security
software you'll ever need

There are many good free AV applications available, and almost everyone
has his favorite. Most of the users are emotionally attached to their av
application and will have excellent reasons for not recommending any
other brand.
The most important thing here is that all of the available choices
listed here are better in some respects than in others, and which choice
is better for *you* depends on what you do, how you work, and which
features you use. The way you use your PC is different from others.
Have a look at this:
http://www.spywarewarrior.com/rogue_anti-spyware.htm
and be guided accordingly.
Good info can be obtained here:
http://www.majorgeeks.com/page.php?id=20
and here:
http://www.av-comparatives.org/

If the above is too 'deluging' consider these options:-
Real-time AV applications - for viral malware.
Do not utilize more than one (1) real-time anti-virus scanning engine!
Disable the e-mail scanning function during installation (Custom
Installation on some AV apps.) as it provides no additional protection.
In fact most experts believe that scanning incoming and outgoing mail
causes e-mail file corruption.
http://service1.symantec.com/SUPPORT/nav.nsf/d4578f66d8f00a0188256d4e006aaa94/4b
a5fc8ef939c44c88256c7500723cf0?OpenDocument&src=bar_sch_nam

Avira AntiVir® PersonalEdition Classic - Free
http://www.free-av.com/antivirus/allinonen.html
You may wish to consider removing the 'AntiVir Nagscreen'
http://www.elitekiller.com/files/disable_antivir_nag.htm
or
Free antivirus - avast! 4 Home Edition
It includes ANTI-SPYWARE protection, certified by the West Coast Labs
Checkmark process, and ANTI-ROOTKIT DETECTION based on the best-in class
GMER technology.
http://www.avast.com/eng/avast_4_home.html
(Choose Custom Installation and under Resident
Protection, uncheck: Internet Mail and Outlook/Exchange.)
or
AVG Anti-Virus Free Edition
http://free.grisoft.com/
(Choose custom install and untick the email scanner plugin.)
or
Kaspersky® Anti-Virus 7.0 - Not Free
http://www.kaspersky.com/homeuser
or
ESET NOD32 Antivirus - Not Free
http://www.eset.com/
and (optional)
On-demand AV application.
(add it to your arsenal and use it as a "second opinion" av scanner).
BitDefender10 Free Edition
http://www.bitdefender.com/PRODUCT-14-en--BitDefender-8-Free-Edition.html

A-S applications - for non-viral malware.
The effectiveness of an individual A-S scanners can be wide-ranging and
oftentimes a collection of scanners is best. There isn't one software
that cleans and immunizes you against everything. That's why you need
multiple products to do the job i.e. overlap their coverage - one may
catch what another may miss, (grab'em all).

SuperAntispyware - Free
http://www.superantispyware.com/superantispywarefreevspro.html
and
Ad-Aware 2007 - Free
http://www.lavasoftusa.com/products/ad_aware_free.php
http://www.download.com/3000-2144-10045910.html
and
Spybot Search & Destroy - Free
http://www.safer-networking.org/en/download/index.html
and
Windows Defender - Free
http://www.microsoft.com/athome/security/spyware/software/default.mspx
WD monitors the start-registry and hooks registers/files to prevent
spyware and worms to install to the OS.
Interesting reading:
http://www.pcworld.com/article/id,136195/article.html
"...Windows Defender did excel in behavior-based protection, which
detects changes to key areas of the system without having to know
anything about the actual threat."

After the software is updated, it is suggested scanning the system in both
Normal and Safe Mode.

Good luck :)

Avast! or AVG, free versions don't expire.

If you have been running without an anti-virus program, yes, you are
very likely infected. I recommend the free version Avast! at
www.avast.com.

You should also be running at least two anti-spyware programs. Here
are several to choose from:

Spybot Search and Destroy
Adaware
Spyware Blaster
Windows Defender
Super-Antispyware
a-squared

I recommend that you begin troubleshooting by
going to MVP Malke's malware removal site at
http://www.elephantboycomputers.com/page2.html#Removing_Malware and
following the instructions there.

AVG version 8 Free, which also features a spyware detector. I've used
successive versions of AVG for about 7 years now, generally to clean up the
mess on customers' PCs that have been left by junkware such as McAfee and
Norton. You can get the freebie here -
http://www.download.com/AVG-Anti-Virus-Free-Edition/3000-2239_4-10320142.html?pa
rt=dl-AVGAntiVir&subj=dl&tag=button.
When you've installed it, run the Computer Check.

((:o)x