Here are a few questions I’ve received recently from humans like you, and my answers. I have edited and restated the questions a bit, for readability. that week my mailbox restricted questions about watching high-definition television in real moment on a Mac, the future of Palm’s Treo, and remote desktop control.

I currently spend about $50 to $60 per year for Norton protection software. Is that essential when Windows XP has its own safety measure built into the operating system?

Windows XP doesn’t include antivirus or antispyware programs, so you definitely need some sort of add-on defense software. whether 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 considering I have my music and photos on the computer and don’t want to lose them.

There’s no universal reply to your question. In general, I don’t believe folks should replace computers that are working well for them just considering they reach a convinced 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 capability 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 day of Windows Vista to Apple’s new Leopard

I ran the tests again on a singled-out 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 instance, has its own committed 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 protection software from Symantec. However, the pop quiz results were very similar — Leopard started and restarted much more quickly than Vista did.

In that simple experiment, 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 mail 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

Orginal post by Walter S. Mossberg