Your beloved laptop is making weird whirring sounds, or your desktop or tablet won’t start at all. If your computer is acting up—or playing dead—you may need to call in the digital cavalry. Luckily, good computer repair shops can take you from crashed to completely fine. Here’s how to find a pro.

Of all the services Consumers’ Checkbook evaluates, computer repair shops are among the lowest-rated. Some shops fail to get “superior” overall ratings from even 60 percent of their surveyed customers.

To get the best repairs at the best price, you need to deal carefully with the shop you use:

  • Secure price quotes for the work in advance from a few shops. You will find substantial price differences: Even for simple upgrades, some outfits charge twice as much as others for the same work.
  • Provide the shop with a thorough written description of the symptoms prompting the repair visit.
  • Insist on a written estimate before repairs proceed.
  • Decide whether the computer is really worth repairing—or if it’s time for a new model.
  • Before paying, get a detailed invoice, including a description of the fix, date, prices for each element of the job, and warranty.
  • Test the device as soon as you take it home, and return it to the shop—or notify the shop in writing immediately—if it’s still not working.
  • Most computer problems result from software glitches, often caused by viruses and other malware. Click here for tips on how to keep your computer safe.
  • Getting rid of an old computer or other electronics? Wipe all of your data and then recycle it responsibly.