How to permanently delete your PC data

— -- Question:. I'm going to trade in a laptop I'm not using anymore for a new iPad. How can I remove all of my personal information before taking the laptop to the store?

Answer: Most people don't realize that when files are deleted, they aren't really gone. The operating system removes the link to the file and marks the space free. Until it is overwritten with new information, that file is still on your hard drive and can be recovered by anyone with a little know-how. I recommend using the free program Eraser to permanently delete your data. Eraser writes over files with meaningless data, making the files unrecoverable. The program offers many options for deleting files.

Q. I've been trying out some of the free Mac downloads on your site. Now, I need to uninstall some of these programs. I know how to uninstall programs in Windows, but I'm new to Macs. What do I do?

A. Some programs, such as Microsoft Office, install just like they do on Windows. In those cases, there's usually an uninstaller for removing the app. The uninstaller should be in the program's folder in the Applications area. Most Mac programs, however, don't require an installer. Unlike many Windows programs, they're self-contained. These are the programs you install simply by dragging them to the Applications folder or to the desktop. Uninstalling a self-contained program just means dragging the program folder from the Applications folder, or desktop, to the Trash. Empty the trash and the program is gone. However, that isn't always the end of the story. Applications can spread files throughout the operating system, and that can clutter your hard drive. It's much easier to use a free program such as AppCleaner. Once you select a program to remove, AppCleaner automatically tracks down all the remaining data.

Q. I'm concerned about Google's new privacy policy and how the company is going to track me. Should I be worried?

A. On March 1, Google will roll out a consolidated privacy policy that covers almost all of its products. What this change means in practice is that you'll be treated as a single user across all Google products. The first thing to note is that this doesn't change Google's data-collection policies. Google has already been monitoring almost everything you do online for the past seven years. So, what is everyone upset about? Well, there is no way to opt out of the new privacy system and stick with the current arrangement. Some people worry what might happen if a third party gets ahold of their consolidated information. I'm not too terribly concerned. Google has stored all this information for years anyway with few snafus. If the new privacy policy makes you uncomfortable, however, your only option is to move away from Google products. Use Yahoo! or MapQuest for mapping. Stick with Facebook and Twitter instead of Google+ for social networking. Fire up Microsoft Bing for searches.

Q. My credit card company is offering to protect me against ID theft for $20 per month. Does this actually work, and is it worth it?