>Q: I need to watch a Windows Media webcast on my Mac. What software will allow that?
A: Not many sites still require Microsoft's video format these days. For those that do, Microsoft offers a free "Windows Media Components for QuickTime" plug-in (http://wapo.st/glPB73). The free, open-source VLC media player (videolan.org/vlc) could be another option.
>Q: I just bought a new keyboard from a company I don't know. Is it safe? Could this firm have hidden a virus or keystroke logger on it?
A: It's possible but not probable for a hardware item to ship with a virus as a stowaway.
In early 2008, for example, Best Buy apologized after discovering that it had shipped some of its Insignia house-brand digital picture frames with a Windows virus on board.
Two years earlier, Apple had to make a similar confession after selling some video iPods with a different Windows virus stashed on their hard drives.
Considering that history, it's easy to think of a scenario in which somebody has stashed a virus on a new keyboard.
But that would be a dumb way to try to get into the virus business. If you want to get a jump on anti-virus developers, you need to get a virus into the wild via the Web, not the slower medium of container ships or cargo aircraft. There are also far more people who browse the Web than use new keyboards.
So if you have current security software, I wouldn't worry about this risk too much.
(I'm assuming you haven't done anything that would make police or spies anxious to log your keystrokes in particular. If you have, that's an issue beyond the scope of this column.)
>Q: How do I remove Windows XP Service Pack 3 from my PC?
A: Microsoft lists a few remedies, none simple, on its support site (support.microsoft.com/kb/950249). But I can't endorse any of them. The company stopped supporting older, less secure versions of XP in July. If "SP3" really gives you fits, you should uninstall it -- then update your computer's add-on software and try installing this patch again.
>Q: My computer won't boot after installing AVG's anti-virus update.
A: A program meant to protect Windows, the free AVG anti-virus program recently became a menace in its own right.
An update posted in early December can prevent some computers running the 64-bit version of Windows 7 -- by now, the standard on new PCs-from booting up normally.
The error message you'd see in that case reads: "STOP: c0000135 The program can't start because %hs is missing from your computer. Try reinstalling the program to fix this problem."
The firm acknowledged the problem in a posting on its tech-support site. It initially suggested booting Windows into its Safe Mode, then using its System Restore function to take the computer back to a "restore point" and then reinstalling AVG.
The company later added a note (www.free.avg.com/ wwen/faq?num4080) with links to a recovery tool that can run off a USB flash drive.
This kind of meltdown happens too often (meaning, at all) with Windows anti-virus software. For example, in April, McAfee had to apologize after a botched update left some XP machines unable to boot.