Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability.

I am going to start college in the fall and I need a laptop. Uncle Jim, who is a Mac addict, is making an argument for a MacBook with Parallels 3.0 and Windows XP installed. He said that way I would have the best of both worlds. My mom is looking at the price. She said we could get a PC for less money but I want to make sure we’re making the right decision. If money is not an issue, what is your recommendation?

Both your mom and your uncle are correct. You can indeed get a decent laptop from Dell or Hewlett-Packard for less than the $1,099 that Apple’s least expensive Mac laptop, the MacBook, costs. But, in my view, the Mac has a better, faster operating system, better built-in software, and is far less likely to expose you to viruses and other malicious software. Plus, the MacBook itself is a sturdy piece of hardware. And there’s a very good Mac version of Microsoft Office that is fully compatible with files created on the Windows version.

Your uncle is also correct that Macs can run Windows, and Windows software, quite well. However, the solution he suggests, using the Parallels software, which enables Windows use on a Mac, will add significantly to the price. Parallels costs around $60, and you also must buy a full, boxed edition of Windows XP or Vista. While prices for Windows vary, this full version (not an upgrade version) of XP can cost nearly $200, and Vista typically costs more.

So, if money really isn’t an issue, I recommend the MacBook. But, since that is rarely the case in real life, you might want to weigh the cheaper alternatives more carefully. Or, if you do buy the MacBook, I’d hold off on the Windows installation until and unless you find you need Windows programs that have no counterpart on the Mac. The average undergraduate likely won’t.

I am dissatisfied with my Internet service provider and I would like to switch to another one. If I switch, can I keep the same email address? Do I have to keep paying the old ISP if I switch and keep the email address?

It depends on your ISP. If it is America Online, you will be able to drop AOL as your ISP and continue to use your aol.com address, regardless of which provider you use to access the Internet. But, in most cases, if you are using the email address provided by your ISP, you will have to relinquish it. However, I would suggest you consider obtaining an email account that isn’t tied to an ISP, so that, if you have to change ISPs again, it won’t disrupt your email. Among such email-only services are Yahoo Mail, Microsoft’s Windows Live Hotmail, and Google’s Gmail.

Your column last week concerned a navigation device called Dash Express that transmits the speed and location of your car to the company for traffic information purposes. But couldn’t this capability also be misused by the company to track a driver’s whereabouts, or even help issue speeding tickets?

Theoretically, yes. But the company, Dash Navigation, says it retains no personally identifiable information on its servers, and merely collects traffic data from participating cars anonymously. A company spokeswoman says: “If the FBI came in and asked us to find someone, we would have no way of locating an individual car.”

You can find Mossberg’s Mailbox, and my other columns, online free of charge at the new All Things Digital Web site, http://walt.allthingsd.com.

Earlier this week, I visited Dash Navigation, the Sunnyvale, Calif.-based car-navigation device start-up that is being backed to the tune of $42 million by Sequoia Capital and Kleiner Perkins.

There, I got a look at the new GPS device called the Dash Express that went on sale exclusively on Amazon (AMZN) today and was also reviewed by my esteemed colleague Walt Mossberg (Cliff Notes on that: he liked it a lot, but it’s not perfect, although he thinks the $400 Dash signifies a leap ahead in the arena).

A longtime user of such devices–make that a longtime disgruntled user–I have always been annoyed that car navigation has been so removed from the digital and connected revolution taking place everywhere else.

Being able to grab information from the Web and also send it to a device seems an obvious move, so I am glad someone has made it. I am also interested in Dash’s use of devices to help inform the whole system about traffic problems, which will presumably work better as more Dash devices are on the road.

In fact, I am in Los Angeles right now–the epicenter of traffic congestion–and I brought a Dash unit to see how well that works. And I also sent a map of the hot spots from the HBO series, “Entourage.” First stop for breakfast after avoiding traffic on Fairfax: Canter’s, the very funky deli the “boys” get food from.

My review: The knishes were delicious and I was not annoyed either, since I was not stuck in bumper-to-bumper traffic getting to them.

Here’s a video I did while visiting Dash’s HQ earlier this week: