Q: A few weeks ago, my Windows 8 laptop unexpectedly started loading Windows 8.1, and there was no way I could stop it. Since then, my screen has been so dim that it's hard to see, which is a problem because I do business accounting with it.

Using the keyboard buttons, I can brighten the screen, but after a few seconds it goes dim again. What can I do?

Susan Applegate, Hollywood, Fla.

A: You aren't the first person to have PC problems after a sudden and unexpected upgrade from Windows 8 to Windows 8.1 (see tinyurl.com/q7zvxe6). This appears to happen on PCs that are set to update Windows automatically.

Other Windows 8 users can avoid an unexpected operating system upgrade by changing the Windows update settings to "download updates but let me choose whether to install them" (see tinyurl.com/ceqpbwj). One strategy is to install only updates labeled "critical."

Fortunately, there are several ways to adjust screen brightness besides the keyboard method. To brighten your screen with Windows 8.1, you can:

Use the "settings" icon found in the "charms bar." Click the "brightness" icon and move the slider up to make the screen brighter.

Or you can click on the "power system icon" (it looks like a battery next to an electrical plug) in the taskbar at the bottom of the screen. Click "adjust screen brightness," and at the bottom of the resulting menu, move the slider control to the right to brighten the screen.

Alternatively, you can change the "power plan settings." Click the same power system icon as before, then choose "more power options." On the resulting menu, check the box next to "high performance," and to the right of that click "change plan settings." Near the bottom of the next menu, click "change advanced power settings." In the resulting list, you can increase the screen's "display brightness" to as much as 100 percent (it's often set at less). When your laptop is running on battery, a higher display brightness will use it up faster.

For an overview of these screen-brightening options, see tinyurl.com/kjv2yds.See tinyurl.com/bpmk85s for details on changing the power plan settings.

Q: How can I transfer my purchased iTunes songs from my iPhone 4 to a new iPhone 6?

Philip Kowitz, Coon Rapids

A: Transfer the songs by backing up your iPhone 4 to your computer or to Apple's online iCloud service, then copying the data to the iPhone 6.

The iPhone 4 backup to iCloud is free, though your phone must be plugged in to electricity and connected to Wi-Fi. When you set up the new iPhone 6, tap on "restore from iCloud backup."

Or you can back up your iPhone 4 to iTunes on a computer via a USB cord. After setting up the iPhone 6, connect it to iTunes and choose "restore backup." For more, see tinyurl.com/qz4xl2v.

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