Generally, virus scans are directed by the user. All antivirus programs I'm familiar with allow for an option to scan multiple drives. You'll need to confirm that the scan is checking ALL drives instead of just the C: drive.
If a virus gets on your external hard drive, then it WILL usually pass to other portions of the computer's drive set up. BUT...It depends on the virus and a number of other things. If an infected "file" was detected on the removable drive, it doesn't necessarily mean that the virus was "executed" and therefore caused an infection on the rest of the machine but it depends on the circumstances of how it got there. If you're going to be moving the external drive from one computer to another, YES, it's possible to spread viruses from one to another from the external drive.
Hope this helps.
Grif
I have an external hard drive, which is not installed yet. My question is when I scan my computer with my antivirus program, will it automatically scan the new hard drive?
Also, if a virus is detected on the external hard drive, will the whole computer be infected too?

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