I'm being barraged with questions from readers who followed my advice and postponed installing Microsoft Vista. They want to know whether it's time now. The answer isn't the same for everyone.

If you have a computer running Windows 98, Windows ME or even XP and your computer has a processor with a speed measured in megahertz, I'll give it to you straight: You are never going to upgrade to Vista. You need to wait until it's time to buy a new computer.

Vista Home Premium requires at least a 1-gigahertz processor, 1 gigabyte of RAM and a 40-gigabyte hard disk with 15 gigabytes free.

Maybe you're running Windows XP on a computer with the required 1 gigabyte of RAM and have a hard disk that's big enough. And the processor is just a touch faster than the 1-gigahertz minimum. As far as Microsoft is concerned, your PC gets a passing grade.

But it flunks in my class. If you are in this group, please stick with Windows XP. Microsoft wants a lot of PCs to fit the specifications for Vista so it can sell more copies. But I think it's really stretched things to the breaking point with the minimum specifications.

We'll call your group the squeakers -- you barely squeak by the minimum specifications. Stay where you are. Vista probably will run on your machine, but by upgrading you'll get slower performance and, I can guarantee it, you'll end up adding RAM, a new hard disk and a new video card. Once you've done all that and then start totaling up the cost, you'll realize you've thrown good money after bad.

That leaves you fast-laners. Your computer has a processor that's faster than 2 gigahertz, your hard disk is 80 gigabytes or better and you have at least 1 gigabyte of RAM.

It's time for you to consider moving to Vista. Most of the early bugs are out. But don't feel too smug; you might have some work to do.

Let's start with the RAM in your machine. Before Vista, 1 gigabyte was considered generous. But to get about the same performance with Vista, you'll need to double the RAM.

You also might discover that your video card is slowing things down. I recommend a card with 256 megabytes of memory instead of Microsoft's recommended 128 megabytes.

You'll end up spending about $200 for the RAM and video card, but I think the upgrade is worth it for people in this group. Vista really is better than XP. It's more secure, a heck of a lot prettier and even has better free accessory programs. I love the new e-mail program that comes with Vista. The spam filtering is as good or better than any commercial product I've used. And backing up your data is a breeze.

We're nearly done here.

Wait. There are a few people left, smirking and giggling.

Be quiet and go back to your Macs.

Bill Husted writes for the Atlanta Journal-Constitution.

bhusted@ajc.com