Question: To get a lower price, I purchased a new laptop with Windows 10 running in “S mode.” I understand that S mode is supposed to be more secure, but that my software choices are limited. (I also know I can upgrade to full Windows 10, but I’m not sure this PC could handle it.) But I’m trying to figure out security. How can I do a manual antivirus scan? Will the Microsoft Edge browser protect me while I’m online? — S.O., Hopkins, Minn.

Answer: Microsoft changed a few rules in its Windows 10 operating system when it introduced S mode, a downsized version of Windows 10 that typically comes on a PC costing less than $300. While S mode is Windows 10, it does a lot less. But, if you are willing to compromise on performance to get a less expensive computer, it’s an acceptable basic PC. Here are some of the differences between Windows 10 and Windows 10 running in S mode:

• Operating system upgrades. You are allowed to upgrade Windows 10 in S mode to full Windows 10 Home for free — but once you have made the switch, you can’t go back. Why does this matter? Microsoft lists the same computer system requirements for both operating systems, but the S mode version is the one that will run well on a minimally equipped, sub-$300 PC. So, if you upgrade to full Windows 10 (see tinyurl.com/mw7m4764), your PC will run slower.
• Advantages. Besides the fact it will run on a low-cost PC, Windows 10 in S mode is supposed to have the advantages of speed, energy-efficiency and more protection against viruses. But the truth is, you only get those benefits as a result of the operating system’s limitations. For example, S mode is faster and more energy-efficient because it runs far fewer types of programs than full Windows 10 does, and uses a less-sophisticated computer. It’s more secure because you are limited to using only apps from Microsoft, which promptly fixes security flaws in its software. (Microsoft has borrowed this concept from Apple. The iPhone operating system is safe because all its apps come from either Apple or its App Store, where Apple enforces security standards.)
• Software. Even though your software choices are limited to Microsoft apps, that’s not all bad. The latest version of the Edge browser is about as safe as Google’s widely used Chrome browser, and the Windows Security program is quite effective. (Your problem with the antivirus scan stems from the reduced functionality of S mode. Microsoft gave it fewer options for manually controlling security, so you probably can’t initiate a scan of your PC.)
• Given its limitations, who is S mode really for? Microsoft aimed it at the budget computer market, which consists largely of schools. There, S mode competes against another limited-function computer, the Google Chromebook, which starts at less than $300 but can cost more.

Question: I like to play MP4 video files that I receive via email. Is there a way to play a video file in Gmail, instead of downloading it to my PC to play on a Windows 10 video player program? — G.B., Eau Claire, Wis.

Answer: You can watch video in Gmail by downloading “Gmail Mod” (mod stands for modification.) It’s an add-on program for the Google Chrome (see tinyurl.com/5vxushjx) or Mozilla Firefox (see tinyurl.com/yp62k6vk) browsers. Gmail Mod plays four video file formats (including MP4), plus three audio file formats.