Windows 7: How low can I go with Windows 7?

I love Windows7. All of the computers at my home are running it, and they all are working perfectly. My school has Windows7, and it works perfectly there too.

However, there's just two computers that I have that don't have 7 on. One is a computer that the entire family uses, has 4 user accounts, tons of files, settings, etc. That computer is fairly decent for being 4 to 5 years old. Its got 1.25GB RAM, 80GB HDD, Nvidia graphics, Intel Pentium 4. I attempted 7 on that with no luck, unfortunately, it ran terribly, and that computer is sticking with XP.

The other computer is slightly weaker, and is my personal machine that I use as a secondary/backup computer. Its a Dell Optiplex GX270, with an Intel Pentium 4, 512MB RAM, 80GB HDD, integrated graphics. Its currently got XP SP3 on it and is working great but I'm starting to not enjoy XP anymore. Its just so boring if you know what I mean .

So I was just wondering.....how do you guys think the Dell would work with Windows7? If I don't install too many programs and store as much as I can on my external hard drive? Would it work, or should I just stick with boring old XP? Which edition/Office edition should be installed?

Thanks so much for the help !

Although, Seven is great, any OS is only as good as it's hardware.
See here Windows 7 system requirements - Microsoft Windows

Windows 7 runs fine on Pentium 4 in most cases. You may have had driver or other issues without enough troubleshooting. 528mb RAM would be a problem unless you can upgrade to at least 1gb.

You can always try it on a second partition for temporary Dual Boot, same as here: Dual Boot Installation with Windows 7 and Vista - Windows 7 Forums

To get a heads up on hardware, programs and drivers run Windows 7 Upgrade Advisor

There is a great deal now on Home Premium Family 3 pack - 3 licenses for about the price of one $129 on Amazon. Retail copies can migrate for life.

Thanks everyone for the quick replies !

I've decided that this computer is just too old to spend any money on, so I won't be upgrading any hardware. I've already got my TechNet subscription so I don't need to worry about getting 7, think I'll try a dual-boot, just to be safe. I'd rather have a boring fast system than a fun slow one lol. I'll also run the upgrade advisor, my only concern is that Aero probably won't work, though.

Since you have so many Windows 7 boxes already, why not take a walk on the wild side and try something different on the older machine like a light weight Linux box. You will learn lots of new things along the way, instead of just doing the same thing all over again...just at a much slower speed.