Q.I have upgraded two desktop PCs to Windows 10 and would like to be able to converse with Cortana, but I don’t know how and I can’t find out. Can I buy a headset and microphone combo that will let me talk to her? If so, what type and where and how will I plug it in to my PC?

A. If your desktop computers did not come with microphones, you should still be able to command Cortana, Microsoft’s Windows 10 customizable virtual assistant, with an external or headset microphone. First, though, confirm that Cortana is enabled in the Windows 10 settings and that neither PC came with a microphone. Go to the Windows 10 search box in the lower-left corner of the screen, type in “Manage audio devices” and open the settings box from the results list. Click the Recording tab and see if a microphone is listed.

If you have a microphone listed, go back to the Search box, type “Set up mike,” and when the “Set up a microphone” option appears, select it and follow along. If the process works, Cortana should hear you. (Microsoft’s website has troubleshooting tips for general sound problems if you do not hear any audio.)

No luck — or no microphone — on either PC? Depending on your computer hardware, you can either buy an external microphone or a headset-microphone. Prices can be as low as $10, but you typically get better audio quality if you pay a bit more.

Microphones can connect to either a dedicated microphone jack on the computer or an available USB port, so where you connect the new hardware depends on the type of microphone or headset you buy. Once you have the mike connected, follow the instructions that came with it (or use the Windows 10 setup option mentioned above) to configure it.

Upgrading an iMac

Q.How do I find out if my iMac can upgrade to the next version of OS X?

A. OS X 10.11, also known as El Capitan, arrives Sept. 30 and should run on any Mac that can handle the current OS X 10.10 Yosemite system. According to Apple’s upgrade guide for Yosemite, you need an iMac from 2007 or later to use El Capitan and be running Mac OS X 10.6.8 (Snow Leopard) or later.

To see information for your particular iMac, go to the Apple menu in the top-left corner of the screen and select About This Mac. Your current version of OS X is displayed, and if you do not see a model year listed for your Mac, click the More Info button.

TIP OF THE WEEK YouTube’s list of similar videos (displayed next to the one you are watching in your computer’s browser) can keep you entertained for much longer than you probably anticipated — especially because the site’s Autoplay feature will start playing the next clip in the list automatically unless you pause or stop the process with the on-screen controls. If you find that the Autoplay function is a little too convenient (or inconvenient, if you are watching videos on your work computer), you can turn it off.

Look for the blue Autoplay button above the Up Next list on the right side of the screen and click the switch to Off. You can also disable Autoplay from the video window itself, even in full-screen view, by clicking the cog-shaped Settings icon in the lower-right corner of the window and clicking the button next to Autoplay. Later, if you want to let Autoplay resume control of your video viewing, reverse the steps to enable the feature again in the YouTube settings.