What you should do if you have a Trojan virus?

Answer 1

One note of correction: a Trojan or Trojan horse is "malware" not a "virus". A virus spreads independently while a Trojan requires you to intentionally install the software containing the hidden malware (the fact that the malware is hidden in an apparently legitimate piece of software is where it gets its name by analogy to the Trojan Horse of Greek Mythology).

If you realize you have a Trojan on your computer, you should go to the store and buy an anti virus kit or packet and install it. Nearly all good anti-virus programs will detect and clean up Trojans. A couple of caveats are in order however. Sometimes a Trojan will corrupt files such that they cannot be recovered. All the anti-virus can do is remove the Trojan and sometimesrepair affected files. When repair fails, your only recourse is to restore the corrupted files from a backup or reinstall the software that the corrupted files were part of in order to get back the uncorrupted files. A few Trojans can also contain boot-sector malware or rootkits. These are a good deal more difficult to detect and remove.