Ask Leo! #552 – Changing the default program, Subnet masks, Having fun with your tech, and more…


How do I change the default program to open a file?

I have this great program for viewing images, but no matter what I do when I double click on a picture I get Windows Image Viewer. That's not what I want! How do I change that and make it stick?

Most programs set themselves up to be the default handler for the types of files they support when they are installed. That means when you installed whatever program it is you're talking about, it should have set itself up (or offered) to be the default picture viewer, making it the program that displays a photo when you double click on one.

Unfortunately that "file association", as it's called, is not only easy to overlook at install time, it's also easy to break.

There are many ways to re-create the association. I'm going to show you what is perhaps the simplest, albeit not the most obvious, way to change the default program.

Continue Reading: How do I change the default program to open a file?

What is a "subnet mask"?

I keep seeing the term "subnet mask" when I configure network stuff. What is that?

Well, to be blunt, it's something you probably never need to know about. Sure, you may have to enter one into a router configuration, but it's typically something you'll be given without needing to know exactly what it means.

You want to know anyway, don't you? Fair enough.

A subnet mask is just a nifty way to define sub-networks. Besides being completely unhelpful, that definition actually opens up a slightly larger can of worms.

Continue Reading: What is a "subnet mask"?

How do YOU use your computer for FUN?

Continue Reading: How do YOU use your computer for FUN?


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Glossary Term


A passphrase (or pass phrase) is simply a password that is constructed using multiple words. Typically, though not always, a passphrase is space separated as one would type normally.

The advantage of a passphrase is that it's significantly easier to remember than complex passwords and therefore can be significantly longer. Much longer passwords are generally considered more secure, even when they're composed of common dictionary words. Even then, a simple alteration – perhaps replacing all of the spaces with periods or all of the letter Os with number 0s, which can be easily remembered – can further obfuscate and make even dictionary-based attacks a practical impossibility.

The limiting factor is typically the system on which the password is to be used. Many do not accept spaces or allow for a sufficiently long password for a pass phrase to be used effectively.

One example of a passphrase is "correct horse battery staple", made popular by the webcomic XKCD. It also shows that the phrase need not even make sense, as long as it's memorable.

Glossary Terms are featured selections from The Ask Leo! Glossary.
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Featured Comments

Should I Upgrade to Windows 10?

Steven writes:

From a user's perspective, Windows 10 is mostly about winning you back after the Windows 8 fiasco. The Start menu is back and if you look closely, it's remarkably similar to the Windows 7 Start menu with the columns reversed. In Windows 7, you pinned items to the left column but not to the right column; in Windows 10 it's the opposite. If you can get past the fact that it looks different, the new Start menu does everything the old Start menu did.

From Microsoft's perspective, Windows 10 is mostly about catching up to the competition. Whether or not you want a personal digital assistant, Apple's got one, Google's got one, so Microsoft has to have one, too. The new Edge browser is Microsoft's attempt to catch up to Google Chrome (and Mozilla Firefox.)

The only really 'new' feature in Windows 10 is Task View, which allows you to have multiple desktops (something Linux has had for years.) Beyond that, there's no talk about improved performance or innovative technology.

Microsoft really wants you to switch to Windows 10 - why else is it a free upgrade - because it desperately needs to catch up. But if you're currently using Windows 7 you have no reason to upgrade, in my opinion, particularly if Chrome is your web browser. Why 'upgrade' to an OS that tries to re-create what you already have? If you're currently using Windows 8 or 8.1 /without/ a third-party Start menu replacement, you'll be much happier with Windows 10. If you /have/ a Start menu replacement, you should upgrade to Windows 10 only if you're excited about having a busybody digital personal assistant who spills everything she knows or guesses about you to Microsoft.

Mark Jacobs writes:

Just a fan theory. Most of the innovative changes come with the unpopular versions of Windows (eg VIsta, 8), when Microsoft realizes they improved the system but pissed off most of their customers, they fix the user interface and everybody praises the new OS.

So, the compelling reason for 7 users to upgrade to 10? To take advantage of all of the speed and efficiency improvements in 8. People complain about 8, but it starts up so fast, and not one question has ever come in to Ask Leo! (well maybe a couple) about slow startup in Windows 8 which was a common problem with earlier versions of Windows.

Windows 8 is the Microsoft Edsel. (For those too young to understand the reference

What do spam filters look at?

SGKris writes:

Thanks for detailed explanation. Most of those points are pertinent only after a mail is opened. Is it not true that opening a spem itself could sometimes lead to problems ? I hover the mouse on the "From Name' and if shows an unfamiliar or strange id, I delete it without opening it. I hardly get any spam and so it is not difficult to do it that way. Is there any other better way ?

Leo writes:

In most email programs it is perfectly safe to open spam. Important part is that you never click on the link in the spam and the images are never displayed in the spam message.

How do I edit a reply?

William Wereb writes:

What really irritates me is the emails I receive with a hundred or more legitimate email addresses in the headers.

The spammers love to see all these addresses. I am sure you have seen the same.

When I ask some of the senders to edit them out I typically get the same answer, "I don't know how to do that"

I have directed a number of them to your site and asked them to join and take a few minutes to read your tips.

Does it do any good, usually not. If I am sending or forwarding to more than one person my email goes out Bcc.

This comment from a 72 year old that knows that you never stop learning if you are willing to continue learning!

Keep up the good work!

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Posted: June 16, 2015 in: 2015
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