Virus Symptoms
- A message appears that a downloaded document contains macros, or an application asks whether it should run macros in a document. (It is best to disable macro if you cannot verify that they are from a trusted source and that they are free of viruses or worms.)
- A program takes longer than normal to load.
- The number and the length of disk accesses seem excessive for simple tasks.
- Unusual error messages occurs regularly.
- Less memory than usual is available.
- Files mysteriously disappear and appear.
- Strange graphics appear on your computer monitor, or the computer makes strange noises.
- There is a noticeable reduction in disk space.
- The system cannot recognize the hard drive when you boot from a floppy disk.
- The system cannot recognize the CD-ROM drive, although it worked earlier.
- Executable files have changed size.
- Executable files that once worked no longer work and give unexpected error messages.
- The access lights on the hard drive and floppy drive turn on when there should be no activity on that drive.
- Files constantly become corrupted.
- Strange or bizarre error messages appear.
- Windows error messages about the FAT or partition table appear.
- The hard drive boots but hangs before getting a Windows desktop.
- File extensions or file attributes change without reason.
- The virus scanner software display a message.
- You receive e-mail massages that you have sent someone an infected message.
- The number of bad sectors on the hard drive continues to increase.
- Task manager reveals unfamiliar processes running.
- The Sigverif command reveals that uncertified software is installed
- Your computer running slow than normal
Source: A+ Guide to Managing and Maintaining Your PC by Jean Andrews