Q: I've been having difficulty with Yahoo e-mail. While I'm usually able to reply to an e-mail, I can't compose or forward a message. Instead I get the message "Yahoo is not responding." My friends on Yahoo have similar complaints. What should I do?

Joann Howitz, Fridley

A: You've run into a software conflict between Yahoo Mail and your Web browser's add-on software (sometimes called "plug-ins"). Add-ons give your browser new features, such as the ability to show animation or to interact with Microsoft Office. There are a three solutions: change the Yahoo Mail settings, deactivate your browser add-ons or try a different browser.

The Yahoo settings solution: Your account is probably set to use what's called the "Rich Text" format, which allows you to change the color of text, alter the typeface or vary the text style (such as adding bullet points.) To reduce the potential for conflict with your browser, you need to turn off Rich Text and use Plain Text instead.

To do this, click on the "Compose" icon in Yahoo Mail, and click the left-facing double arrow icon on the toolbar below the e-mail. This will cause most of the other icons in the toolbar to disappear; instead you'll see a right-facing double arrow next to the paper clip icon for attachments.

To disable the browser add-ons for the Microsoft Internet Explorer, Mozilla Firefox, Apple Safari or Google Chrome browsers, see tinyurl.com/pj65r4s.

To download a new browser: Firefox (tinyurl.com/chls6cx), Safari (tinyurl.com/ccnzbon) or Chrome (tinyurl.com/lo6kkkd).

Q: How can I get rid of "PC Power Speed System Optimizer," which I downloaded thinking it would help my computer?

Jamie Kyllo, Albert Lea, Minn.

A: This is a bogus security program that falsely claims your computer is infected with a variety of malicious software, which it offers to remove for a price. There are a couple of ways to get rid of it.

Delete Optimizer while Windows is in "Safe Mode," a minimal version of Windows that will keep the malicious software on your computer from activating.

To start in Safe Mode in Windows 8, see tinyurl.com/pwfwnne. Then in "Startup Settings" choose "Enable Safe Mode." To start Safe Mode in Windows 7 and earlier Windows versions, press the F8 key while the PC is starting up, then from the menu choose "Safe Mode."

Once in Safe Mode, use your ­antivirus program to search for and delete Optimizer. Or run System Restore, which can return your PC settings to a calendar date before Optimizer was installed (see tinyurl.com/ybe3wny).

To delete Optimizer manually: Follow the directions at tinyurl.com/nny766g. Be careful because you're deleting data from the PC's Registry, or settings database, and a mistake can impair the PC's ability to run.

E-mail tech questions to steve.j.alexander@gmail.com or write to Tech Q&A, 425 ­Portland Av. S, ­Minneapolis, MN 55488. Include name, city and telephone number.