Q: What happens to my MacBook Pro's battery, which normally uses an 85-watt power adapter, if I charge it with my daughter's smaller white MacBook 60-watt charger or vice versa? A. Apple currently makes several Mac laptop models and supplies each one with a 45-watt, a 60-watt or an 85-watt power adapter to charge the battery and run the computer on electricity. The company states that you should always use the specific power adapter that came with the computer. But in a pinch, you should be able to use an adapter with a higher wattage than the one that came with that particular Mac -- and without any problems. So while you can use the 85-watt adapter to safely charge the smaller white MacBook, Apple advises against using an adapter with a lower wattage to charge a laptop battery that normally uses the 85-watt charger. Most other laptop manufacturers advise against using power chargers other than the one that originally came with the laptop or a replacement charger made to work with that model; some companies may consider using a different charger as a void on the computer's warranty. Depending on the situation, using the underpowered charger on a laptop battery that needs more wattage could have a number of results. The battery may charge but at a slower rate; the charger may power the computer if it is on but not charge the battery; or the charger's life could be shortened by overheating. Apple has a technical support page that illustrates its various power adapters and has more information on using them with different Mac laptops at support.apple.com/kb/HT2346. For those wondering if it is safe to use an iPad's 10-watt power adapter to charge an iPod or iPhone, Apple's support site states that it is safe. The company says that you can also charge an iPad with the iPhone's smaller power adapter, but that it will take longer to do the job. LOCKING A WORD FILE Q. Can Word files and other files be locked or password-protected by their creators to prevent others from opening them? A. Microsoft Office includes a password-protection feature that lets you lock Word documents, Excel spreadsheets and PowerPoint presentations. In Word 2007, open the file you want to protect and click on the Microsoft Office button. On the left pane, select Prepare and click on Encrypt Document on the right side of the box. Enter and confirm a password and save the file. In Word 2010, open the document; click on the File tab and then on Info on the left side of the screen. In the Permissions area, click on Protect Document, choose 'Encrypt with a Password' and add a password. With the document open on a Mac in Word 2008 or Word 2010, go to the Word menu and choose Preferences. Click on Security, enter a password in the box and click on the OK button. TIP OF THE WEEK Most Web browsers now include a Search box on the toolbar, but in most cases, you are not stuck with just one search engine driving your keywords around the Web. In Microsoft Internet Explorer, Mozilla Firefox, Opera and Apple Safari, click on the small black triangle to see a list of other search engines you can use. In Google Chrome, click on the wrench icon and on the Basics tab, then choose Options or Preferences; use the pop-up menu next to Default Search to change to Bing or Yahoo. If your browser gives you a Manage Search Engines button or menu option, you can also add more search sites, like Wikipedia or YouTube, to your browser's pop-up list in the Search bar. 