michaelr -

MSDOS 3.5 wasn't too bad.

Windows 3.1 gave you a graphic view that was helpful for most people.

Windows 3.11WG added local networking.

Win98 started off with some instabilities, but the update to Win98SE made it reasonably useful. By the time it got to Win98SE SP2 it was fairly stable, but ridiculously un-secure by current needs.

Win2000 was specifically intended for "Enterprise Users" (big business) and was based heavily on Win NT, a much more powerful, mostly command line OS used by (some) businesses for networks and business programs. In some respects it was the most reliable/stable Windows version up to that time, but sometimes offered enough "power" for novice users to hurt themselves.

Win ME (Millenial Edition) was a blunder intended to be a "Win 2000 for ordinary people" that was - putting it simply - pure CRAP.

All of the above are DEAD due to end of support. Because of vulnerabilities to even trivial malware, none should be in use now. (Even if you can manage to keep one operable, you will likely be a source of propagation of malware to others.)

WinXP was fairly well-liked by users, and remains on at least 40% or more of all computers currently running. The percentage quoted varies with who reports usage and is confused by the very large number of counterfeit/pirated copies extant, especially in China. Many people still like it, although having used an older laptop with WinXP on it a few times recently I wonder what it was we liked - simply because it's excruciatingly slow compared to later versions if for no other reason. (But it was a really old laptop, of course.)

An END OF SUPPORT for WinXP has been announced a couple of times, then extended because of protests from the large user base; but support WILL END in 2014, as noted in the first post here.

Vista actually is more stable and much more "secure" than any prior versions, but the user interface is not well liked, and some significant vulnerabilities (that shouldn't have been there) were found after release. Many users have been "unimpressed" with the new interface, so:

Windows 7 is the latest currently available Microsoft OS. While the early advertising slogan was "it's not Vista" Microsoft improved on what people didn't like in Vista by making Win7 "more so, so it's better." (only slightly sarcasticly assessed)

Since very few computers produced in the WinXP era or before will have the hardware resources to run Vista or Win7 effectively, the approaching demise of everything older than Vista leaves only those two as viable options for now, and for nearly everyone an upgrade probably should come installed on a new computer.

Vista (sort of) began the mainstreaming of 64-bit Windows, which of course requires a 64 bit processor. Both Vista and Win7 have 32-bit versions that are okay when run on a 32-bit machine, but performance with the 64-bit version is reportedly much better. Vista 32-bit really needs at least 2 GB RAM and benefits quite a bit if 4 GB is installed, although 32-bit Vista can only use an actual ~3.6 GB of it. (You can't generally install "more than 2GB" without going to 4GB.)

I haven't bothered to look at what the max RAM is for 32-bit Win7, but the recommendations strongly favor going to 64-bit for Win7 for other reasons. Some machines available now with Win7 include 4 GB RAM, but 8 GB would probably be better unless you're a "light user."

Vista 64-bit machines should be able to use 32 GB of RAM, which sort of restores the ability to "have more than you need" if you want to.

Win7 is what most builders are shipping now, although a few vedors still may offer Vista. Win7 introduces a whole new "interface" that I haven't had sufficient experience with to really say how traumatic the changes may be; but complaints about Vista have been sufficient to suggest that most people upgrading now should probably go directly to Win7. Vista is a more secure OS than prior versions, and additional security is claimed for Win7.

IF YOU'RE STILL RUNNING WINXP, you do still have a couple of years before support ends completely, but it would be a very good idea to start thinking seriously about when you'll move on and what you'll want when you do. And for most, you will want to start saving up the cash for a new machine.

WHEN you get a new machine, it probably would be best to get a 64-bit processor since later upgrade paths may be closed for 32-bit ones within a reasonable machine lifetime. Vista, and probably Win7, are "big" so 500 GB Hard Drives would be a minimum I'd suggest for a desktop or "power laptop," and I probably won't buy less than 1T. If you're interested in a notebook/notepad you might get by with something like 300 GB(?). USB-3 is available from some sellers now and would be a very good idea, since with the bigger drives moving half-Terabyte batches of files with even USB-2 can take DAYS, weeks with original USB-1. USB devices remain much more available than alternatives like Firewire, but apply your own preferences there.

Note too that many features advertised are NOT AVAILABLE in the "Basic" or "Home Basic" OS versions, so you might want to consider a "Premium" version. Upgrades are easy, since all recent Windows install disks (or preloads) include all versions, and an upgrade can be turned on with a phone call and credit card, but it's an additional cost that's slightly more than getting the right one preinstalled.

John