Rob Pegoraro

Special for USA TODAY

Q: My old laptop's screen backlight has blown out. How do I connect another laptop to recover the photos and e-mails from this "dark" computer?

A: You don't need another laptop, you need another monitor. And by "another monitor," I really mean an HDTV.

Almost any flat-screen model should have two ports a laptop can easily connect to: a trapezoid-shaped analog VGA input and a flatter digital HDMI input.

Almost all older Windows laptops include VGA outputs, while newer ones offer HDMI in addition to or in place of VGA. Most Mac laptops come with one of several sorts of digital-video connectors that require an adapter to connect to VGA or HDMI: DVI and its micro- and mini variants, or Mini DisplayPort and the visually identical Thunderbolt.

Any recent laptop should automatically detect the screen at the other end of the VGA or HDMI cable. Then you'll need to switch the TV to the appropriate input with its remote; with any luck, your desktop will appear on the larger screen.

Older PCs may need some coaxing. In these cases, you usually tell it to switch to an external display by pressing whatever function key features a little icon of a monitor. For example, Dell laptops need you to hit Fn and F8 at the same time, but HP models require Fn and F4. Wait at least five seconds before cursing at the computer like every other presenter who's tried to connect a laptop to somebody else's projector.

I've yet to see a Mac not detect an external display. But if you only see a blank area of your desktop, without any open windows or a menu bar, try hitting the Command and F1 keys to switch OS X back to mirroring the built-in screen.

You could also use a standard computer monitor for this job instead of a TV. But looking at how desktop sales have cratered, I'll bet that far more of you own an HDTV than have access to a spare CRT or LCD monitor.

(Analog televisions, however, lack VGA and HDMI ports and, more importantly, the resolution to mirror a laptop's display clearly. So in that case, see which friends or neighbors have a spare HDTV or monitor.)

Apple's OS X offers a workaround that would better suit somebody looking to rescue data off an unsalvageable laptop before wiping their user account from the machine and recycling it: the "target disk mode" option that enables a second Mac to browse and copy the contents of the first as if it were an external hard drive.

To use that, connect both Macs' FireWire or Thunderbolt ports (as with video output, you may need an adapter), then hold down the "T" key as you boot the damaged Mac. The second Mac will then show the first Mac's disk as yet another icon on its desktop.

Windows doesn't have an equivalent of this feature, although if you can remove the hard drive you can pop into a cheap drive enclosure and then plug that combination into a second computer.

If you're truly desperate to use a laptop without a functioning backlight, I can report from my own experience with them (don't ask) that you may be able to make out what's on the screen if you look at it up close and from one side.

TIP: BYPASS SCANNER-DRIVER PROBLEMS

Just because I write about computers for a living doesn't mean I always know what I'm talking about. And so it fell to my wife to point out that the Canon Wi-Fi printer/scanner we've owned for years doesn't need a computer's help to scan a document or photo; you can pop a USB flash drive or SD card into it, use its own controls to do the job, then plug the drive or card into a computer.

In general, any all-in-one model with its own buttons and display as well as a USB port and memory-card slots should be capable; see, for example, documentation from Canon, HP and Lexmark.

This option can come in handy if you're borrowing somebody else's scanner and don't want to bother installing drivers for it — or, perhaps more likely, your own computer's scanner drivers are acting up or stopped working after an operating-system upgrade.

Rob Pegoraro is a tech writer based out of Washington, D.C. To submit a tech question, e-mail Rob at rob@robpegoraro.com. Follow him on Twitter at twitter.com/robpegoraro.