symptoms of computer virus | Unexplained slowdown of the system

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.