Virus infection symptoms
Some of the very common symptoms shown by a virus are given next.
Unexplained slowdown of the system
This is one main symptom of the virus infection. If the system without any apparent reason starts to take more time to load programs from the disk or starts to operate slower than its normal speed then you can suspect a virus infection.
Decrease in the amount of available memory
This is another symptom of virus infection. When checked with the CHKDSK, the system shows some KB of memory missing from the main memory or when checked with the MEM/D/P command, the memory module list shows some program resident in the memory without any proper module name.
Increase in bad sectors/lost clusters etc.
When the number of bad sectors start increasing, or when the number of lost clusters reported by the Scand disk or CHKDSK start increasing without any special reason them one main reason behind this could be a virus infection.
Cannot execute executable files
If you find that the executable files (.exe, com etc) which able to execute till yesterday start missing from the directories or when executing them you start getting some error messages then this again could be one major indication of the virus attack.
Screen shows some unusual outputs
Getting of some message such as “ legalize marijuana” or dropping of letters to the bottom of the screen or some special character appearing or moving around on the screen or blank spots on the screen etc. could also be a symptom of virus infection.
Another indication could be some music being played by the computer without running any specific music program.
Drive’s light turns on
The drive’s light may turn on indicating that a read or write is taking place even when you have not given any read or write command, or when you have put a read only disk in the drive the system tried to write to the disk without any write command being issued are some other symptoms of virus infection.
Some software such as windows keep temporary data on the disk and read and write to them periodically.
New “.COM” files appear for the “.EXE” files.
This shows a companion type virus where the virus stays as a .COM file for and .EXE file. This gives the virus a chance to get executed because the dos always executes the .COM file before executing a .EXE file if both the files are of same name.
Some DOS program and utility programs contains both .COM and .EXE file with the same name . for example, the DOS program MSD(Microsoft diagnostic) contains both MSD.COM and MSD.EXE.