Prevent Viruses From Disabling Your Protection
Restore your PC's antivirus defenses and ensure that they aren't blocked again.
Some viruses protect themselves by blocking security Web sites, antivirus programs, and other tools that could be used against them, including Windows' System Configuration utility (Msconfig) and Registry Editor (Regedit). They cleverly block antivirus Web sites by altering your Hosts file--a text file with no extension that individual programs use to assign a specific IP address to a Web page. In Windows XP, this file is in the C:\Windows\system32\drivers\etc folder; in Windows 2000, it resides in C:\WINNT\system32\drivers\etc; and in Windows 98 and Me, it inhabits C:\Windows. To correct the problem, double-click the Hosts file and choose Notepad or another text editor to open it. Delete any line in the file that refers to an antivirus Web site. Or simply delete the Hosts file; Windows re-creates it automatically with zero entries.
Now browse to an online virus scanner to check your hard drive and (we hope) remove the virus. A good one is Panda Software's ActiveScan (e-mail registration required). It uses an ActiveX control to check your system, so you have to use Internet Explorer.
To keep your system's defenses unblocked, change the extension of any utility's executable file from .exe to .com (which, like .exe, is executable). Thus, for instance, if a virus won't let you edit your Registry, select Start, Run, type command, and press Enter. At the prompt, type ren c:\windows\regedit.exe regedt.com and press Enter. Now the command regedt will launch the Registry Editor.
Change the System Configuration utility's executable file from 'msconfig.exe' to msconfig.com. In XP, this file is in the C:\windows\pchealth\helpctr\binaries folder. In Me and 98, it's in C:\windows\system. (Windows 2000 lacks this utility.)
