‘Delete’ doesn’t really delete your data in most programs

Q: I understand that the Delete command doesn’t really remove files in Windows, but short of using some kind of “erasing” utility, could it be effective in the case of documents such as Word or Excel to simply delete the file contents and resave the file before deleting it? In other words, does saving the old file under its original name as a blank document prevent the originally saved contents from recovery/discovery?

— Glenn Evans

A: As you indicate, when you delete a file the file contents aren’t actually removed from your drive. Instead, the filename “pointer” to the file contents is deleted so you don’t see the file any more. File-recovery programs can help you retrieve deleted files … until those sectors on the drive are overwritten by new data.

Most programs handle deleted data within files the similar fashion. First, a deleted paragraph will be held in the clipboard until it is replaced by a new deletion. You can delete text from a file, save the file and, after reopening it, paste that deleted text right back in.

Also, some programs including Word and Excel allow users to turn on “versioning,” a feature that keeps earlier versions of documents intact. But even without versioning turned on, the text you deleted is not actually wiped out until the sectors of the drive it is stored in are overwritten. It may be difficult to retrieve, but it is there.

In short, if you really want to ensure that data cannot be retrieved you need to use a program that wipes the data by overwriting the sectors where it is stored.

Q: Lately my computer has gotten slow. When I turn it on in the morning it takes time to bring in any new emails. When I search it is very slow. What can this “old guy” do?

— John Logan

A: For starters, there are different kinds of slow. Your computer might be slow because too many applications are running, or a misbehaving program is using up all the computer’s memory or processing time. Or it might be running slow because you don’t have enough free space on your hard drive for the computer to swap data in and out of memory. Or you might have malware on the computer.

But from what you write, it sounds like the problem isn’t with your computer but rather with your internet connection.

You can check whether you’re getting the internet speed you’re supposed to be getting by using your web browser to go to www.speedtest.net. If you’re not getting the speeds you expect there are several things to check on. First, reboot your equipment, including your computer, cable modem, Wi-Fi router — any and all equipment that connects you to the internet. Let it all remain off for at least 15 seconds before restarting.

If that doesn’t fix things, try disabling all extensions in your web browser. Also, make sure no other devices or programs are accessing the internet. If you’ve got Netflix running on that computer or on your internet-connected TV, it could slow down your browsing.

The next thing to try is to set your Wi-Fi router — assuming you’re connecting over Wi-Fi — to a different channel. If your neighbors are using the same channel it may be slowing you down.

Finally, again, it may be that you have a virus or other malware on the computer. Run a full virus and malware scan.