First, if you've been infected by a virus contact IT support. If you're at a university you should have an IT department. If you're a home user without on-site support, you may need to seek outside help. Next, you should disconnect your computer from the Internet. There is a chance, depending on the virus that has infected you, the virus is gaining access to your personal information and may be using your computer to harm other computers. If you disconnect your Internet connection, that access will stop. You should back up your files. You can't be sure how much the virus will damage and so you'll want to save important files. Then install an antivirus program and scan your computer. The program should detect and remove the malicious files. Then you are safe and sound.