Q. Recently I’ve been unable to send emails from my home email address. In addition, my incoming email contains several notices of undeliverable emails that I didn’t send that are addressed to people I don’t know. I suspect that my computer is infected by some malicious software and is being used to send spam email — and that those that are undeliverable are being returned. What should I do?

Joseph Campbell Burnsville, Minn.

I agree that your PC has been taken over by hackers and is being used to send spam.

The fact that you aren’t able to send emails from your home account supports this theory, since it indicates that your Internet service provider believes you are spamming and has temporarily blocked your ability to send email to anyone.

I suggest you download and run the free version of security program Malwarebytes (go to www.tinyurl.com/cwbd73f and click “free download.”) If that doesn’t work, try Windows System Restore to eliminate recently installed software (see www.tinyurl.com/y9q9apj and www.tinyurl.com/ykgps6.) Then call your Internet service provider; explain what happened and what you’ve done to fix it. If your PC is clean, you’ll be allowed to send email again.Q. I’ve recently received a lot of spam, including some that appear to be from people I know — except that the messages come from the wrong email address. How does a spammer use a familiar name with a fake email address and send it to me?

Also, is there a way to find out the identity of the people who send spam emails? I’ve read that the email address of the sender is not always accurate.

Ginger Bramlett Rockwall, Texas

The bogus email that appeared to be from your friend, but came from the wrong email address, is from a spammer who is trying to trick you into opening the email.

Why did this happen? Your friend’s email may have been hacked and his or her address book stolen, providing the spammer with a host of addresses where an email bearing your friend’s name might be opened by the recipient.

It’s hard to find out who actually sent spam, because originating email addresses are easy to fake.

I suggest you send these emails to your spam filter so that you and others may be spared at least some spam in the future. In addition, your Internet service provider allows you to block spam that comes from a specific domain name — the part of the email address that follows the symbol, such as Yahoo.com. See www.tinyurl.com/cxmq4m7.