GO TO MsDos:

C:\> CD\

C:\> MD TEST

C:\> CD TEST

C:\TEST> COPY CON COM.COM

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 HOLD ON TO THE KEYS <CTRL> + <Z> TO SAVE THE COM.COM FILE

C:\TEST> COPY COM.COM+COM.COM+COM.COM EXE.EXE

AN EXE.EXE FILE OF THE TRIPLE SIZE COM.COM IS CREATED

C:\TEST> TYPE EXE.EXE

C:\TEST> EXE

...ANY ASCII CODES PRESENT INSIDE THE EXE.EXE FILE REVEALS A VIRUS IS INSIDE THE COMPUTER MEMORY...

...SAME GOES TO THE COM.COM FILE TO TEST IF THE VIRUS WILL COPY ITSELF INTO A CERTAIN BYTES OF SIZE OF A COM.COM FILE...

C:\TEST> COPY EXE.EXE+EXE.EXE+EXE.EXE COM.COM

...OVERWRITE THE COM.COM FILE...

...A COM.COM FILE TRIPLE SIZE OF EXE.EXE IS CREATED...

C:\TEST> TYPE COM.COM

C:\TEST> COM

...ANY ASCII CODES PRESENT INSIDE THE COM.COM FILE REVEALS THAT A VIRUS IS INSIDE THE COMPUTER MEMORY...