How to clean out a hidden computer virus in a computer program?

I know how to use an antivirus software but i want to know how to clean a virus out of a computer program. I ordered this software and it turned out to be pirate and I am not sure how to clean it out.

Do use a debugger or somthing? if so what do I look for

How to clean out a hidden computer virus in a computer program?panda

Hidden Virus also called backdoor trojan or rootkit. You can download AVG Anti-Rootkit (Free) to remove the virus.

How to clean out a hidden computer virus in a computer program?suzuki

u got what u paid for- just remove the program and buy the real thing
pretty much what those guys said (above). This sh!t is in your registry and if you dont know what you're doing, you can totally screw up your PC by even daring to go into registry.

Get a good antivirus/antispy--I like PCillin by Trend Micro. You can download it at their site or buy it and install it yourself (recommended if you have a virus--sometimes it wont allow the download of the antivirus software--it'll LOOK like it's loading but it will block it).
The best tools I have encountered are rootkit removers and the following anti-virus engines: Antivir, Kaspersky, ADAWARE by Lavasoft, Spybot Search and Destroy.

Very unlikely you will have problems after you have used these, of course the first ones are limited because you have trial versions, if you want free then Spybot Search and Destroy, and AVG will keep you reasonably well protected and do not consume your resources, there is Nod By ESSET but I find it too limited in certain areas.
Norton, AVG , Avast are free antivirus software. Ad-aware, Ewido are free spyware removers. You can download free softwares at http://fixit.in/antivirus.html and http://fixit.in/spywareremover.html . You can also run a free registry scan using utilities from http://re7.info
You can't clean it, use Avast
If your virus software can not clean it, the software is the virus, get rid of it. There is no way to safely decompile a program containing a virus and that is the only way you could do anything with it. You would need to be an expert programmer to read other people's programming, it is far more difficult than writing your own.
A good idea is to use AVG antivirus. For some people it works better than High priced anti virus systems. If it seems that the antivirus program is removing the virus yet it keeps coming back, stop you system restore by right clicking My Computer, click on the System Restore tab and disable it, then rescan. Keep System restore disabled for a while and eventually it should go away.