How do I check to see if my system contains a virus? Discussion You should always be cautious of virus infection if your computer begins acting unpredictably (random lockups, frequent intermittent errors, etc.). This is especially true if you regularly access the Internet or transfer files using floppy diskettes. Even without anti-virus software, there are a number of ways to determine whether your computer contains a virus. Although these methods of detecting viruses are not foolproof, they provide a starting point for diagnosing your system. Solution Under MS-DOS®: Method One - Running CHKDSK: Boot to a DOS prompt, and type: CHKDSK <Enter> Where <Enter> is to press the <Enter> key once. Find the line containing total bytes memory. On this line, you should see the number 655,360. If the amount of total bytes memory is something other than 655,360 (typically 653,312) you hard drive may contain a master boot record virus. NOTE: Some SCSI adapters and BIOS routines reduce this number as well. Method Two - Checking for viruses attached to executable files: Boot to a DOS prompt. At the DOS prompt type: chkdsk <Enter> Where <Enter> is to press the <Enter> key once. Look for the lines containing total bytes memory and bytes free, and write down the numbers given to the right of each line. For systems using MS-DOS and Windows 3.x, Type: cd \dos<Enter> or for systems running Windows 95/98 cd \windows\command<Enter> Type: dir move.exe<Enter> and write down the size and date of the file move.exe. Type: move<Enter> (this command will return Required parameter missing). Once again type: chkdsk<Enter> and note the total bytes memory and bytes free. Next type: dir move.exe<Enter> Note the file size. If either the total bytes memory, free memory, file size, or file date has changed, your system may be infected by a virus. NOTE: You may also run these tests on systems running Windows® 95/98 by booting to a Safe Mode Command Prompt. To boot to a Safe Mode Command Prompt under Windows® 95 press the <F8> key at the top of the keyboard during the boot sequence once you see the message Starting Windows 95. This displays a boot menu containing the Safe Mode Command Prompt option. Under Windows® 98 press <Ctrl> before the Windows® 98 "splash screen" to reach the boot menu. Under Windows® 95/98 Check the Performance tab: Click the Start button, click Settings, and then click Control Panel. The Control Panel window will appear. Double-click the System icon. Click the Performance tab. Under Performance status look for File System:. The file system should read 32-bit. The last line under Performance status should read: Your system is configured for optimal performance. If the file system reads All drives are using MS-DOS compatibility mode, and the last paragraph contains Master Boot Record modified, your system is likely infected by master boot record virus. Another indication of virus infection under Windows® 95/98 is a sudden disappearance of your CD-ROM drive. To check for disappearance of the CD-ROM drive double-click the My Computer icon, and look for the icon corresponding to your CD-ROM drive. If the icon is not present, you may have contracted a virus. Under Windows® NT: The following message while booting to Windows® NT may result from virus infection: STOP: 0x0000007B Inaccessible Boot Device Possible virus related messages occurring during the Windows® NT installation process: Setup displays the message: Setup did not find any hard drives on your computer. Your system reboots continuously after the first reboot. If after removing the third setup disk and restarting you receive the error message, Setup has encountered a fatal error that prevents it from continuing. Contact your software representative for help. The following status codes will assist them 0x4, 0, 0, 0. Removing Viruses If you suspect your computer is infected with a virus, you should purchase and run a commercially available anti-virus package. It is best to run DOS-based anti-virus software from a write-protected diskette. Please, contact the anti-virus manufacturer for instruction on using their software.