What can virus do to your computer once it has been infected? Below are possibilities you may experience when you are infected with a virus. Remember that you also may be experiencing any of the below issues and not have a virus.

• Deleted files.

• Various messages in files or on programs.

• Changes volume label.

• Marks clusters as bad in the FAT.

• Randomly overwrites sectors on the hard disk.

• Replaces the MBR with own code.

• Create more than one partition.

• Attempts to access the hard disk drive, which can result in error messages such as: Invalid drive specification.

• Causes cross-linked files.

• Causes a "sector not found" error.

• Cause the system to run slow.

• Logical partitions created, partitions decrease in size.

• A directory may be displayed as garbage.

• Directory order may be modified so files, such as COM files, will start at the beginning of the directory.

• Cause Hardware problems such as keyboard keys not working, printer issues, modem issues etc.

• Disable ports such as LPT or COM ports.

• Caused keyboard keys to be remapped.

• Alter the system time / date.

• Cause system to hang or freeze randomly.

• Cause activity on HDD or FDD randomly.

• Increase file size.

• Increase or decrease memory size.

• Randomly change file or memory size.

• Extended boot times.

• Increase disk access times.

• Cause computer to make strange noises, make music, clicking noises or beeps.

• Display pictures.

• Different types of error messages.

source : http://www.computerhope.com

Labels: Tips, virus info