My computer takes forever to start up. I am tempted to just put it into hibernation or standby when I am done with it for the day, so that starting up will be quicker. Would I be damaging my computer by doing so?

Doing this shouldn’t cause any damage to your computer. For many users, one of these two techniques is standard procedure, in fact. Standby, or sleep, mode, gets you back to work more quickly, because the machine never completely shuts down. Its biggest downside is that, on occasion, computers fail to “awaken” properly from this mode, and you have to do a full restart. So I would advise that you carefully save any work before initiating standby.

In my experience, this kind of glitch is less likely to happen when you use hibernation, in which the computer does completely shut down, but first saves to the hard disk a record of the state of the machine.

When the computer restarts, all open programs and files are restored just as you left them. The downside here is that getting going again using hibernation takes longer than it does using standby mode. And, even though it’s more reliable than standby mode, I’d still advise saving all your work each time before using hibernation.

I am thinking about switching to a MacBook Pro laptop. I understand that it has a real good automatic Wi-Fi detection system. But if I also use a cellular modem card from Verizon or Sprint to access the Internet, won’t the two conflict?

No. The Mac operating system treats the two kinds of connections separately, each with its own user interface. It can detect and connect either one, if you have coverage of both types.

I’m interested in getting a laptop with LED display and SSD drive. Do you think the price for those components will fall drastically in three months’ time?

Displays that use light-emitting diodes (LEDs) have been around for a while and don’t tend to be a major deal breaker in the higher-end laptops in which they are commonly offered. But solid-state drives (SSDs), which replace hard disks with memory chips to store your data, are much rarer and newer and still can add significantly to the price of even a high-end laptop. I am no expert in price forecasting, but, while SSD prices will fall, I doubt they will drop “drastically” in as little as three months.

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

I currently spend about $50 to $60 per year for Norton Security software. Is this necessary when Windows XP has its own security built into the operating system?

Windows XP doesn’t include antivirus or antispyware programs, so you definitely need some sort of add-on security software. If you don’t want to pay for it, there are free alternatives available.

How do we determine when to purchase a new PC? Our current Dell is about five years old. I’m feeling a little worried because I have my music and photos on the computer and don’t want to lose them.

There’s no universal answer to your question. In general, I don’t believe people should replace computers that are working well for them just because they reach a certain age. On the other hand, five years is pretty old for a PC. At that age, the odds increase that the hard disk may develop problems, and that newer versions of the software you like will require hardware upgrades that may cost more than you want to invest in an older machine.

Assuming your Dell is working fine, that you aren’t a power user, and that your music and photo activities are simple and basic, there’s probably no urgent need to replace the PC. But, to assuage your concern about “losing” your pictures and music, you might back up those precious files to an external hard disk or an online backup service.

Last week, you compared the start-up time of Windows Vista to Apple’s new Leopard operating system, and found Vista to be much slower. But you used different laptops for each. What would the numbers be on the same Macintosh running the two operating systems?

I ran the tests again on a single computer, a fairly new Apple iMac, which can be started up, and restarted, in either Vista or Leopard. I used the Mac’s Boot Camp feature, in which only one operating system is running at a time, has its own dedicated portion of the hard disk and fully controls the hardware. The machine uses an Intel processor and other key components commonly found on Windows machines, and runs Windows just like a Dell or any standard Windows PC, without any involvement from the Mac operating system.

This Vista installation doesn’t include any of the speed-robbing trial software commonly included by PC makers, though it does have security software from Symantec. However, the test results were very similar — Leopard started and restarted much more quickly than Vista did.

In this simple test, I timed both operating systems from a cold start and a restart until the computer was fully ready for operation, with the hard disk quiet and the network connection established. The cold start, beginning with the computer completely off, took Leopard 46 seconds, but took Vista one minute and 42 seconds. A restart, beginning with the computer running an email program, the Firefox Web browser, and Microsoft Word, took one minute and two seconds for Leopard, and three minutes and 17 seconds for Vista.

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

Write to Walter S. Mossberg at mossberg@wsj.com