First things first: if you want to test your RAM, download and burn the ISO file from http://www.memtest86.com/ and reboot from the CD. Memtest86 is *the* RAM tester (well, that you or I can afford and it's free).
Secondly, Linux: it all depends on what distribution you're using. My flavour of the month is Ubuntu. I had a New Year's resolution to be using Linux for everything that I could use it for (practically everything). I'm a little slow on resolutions but having just installed Ubuntu, I still believe I can make it by year's end.
Installing Ubuntu is easier than Windows, no doubt (and don't let the naysayers tell you otherwise). You answer a few questions then a whole slew of software is installed. Drivers for pretty much all of your hardware are automatically installed, too. If you've set up a Windows machine from scratch, you'll agree that Ubuntu is way easier to get to a running state.
Installing software in Ubuntu is generally easier too as it uses software repositories of thousands of applications and a nice little app that wraps them all up. if I want to install a word processor I search for 'word processor', select the one I want and Ubuntu downloads and installs it (as well as anything it requires). Click a button to see if there are any updates for everything that's currently installed: that's nice too.
WINE (the Windows Emulator) is getting pretty good to run Windows apps if need be. It's not fantastic with games, though getting better. Cedega is another program based on WINE (you have to pay for Cedega) and it's main focus is games, so that could be good. Note, though, that a fair few of the games that are coming out now have Linux clients available, anyway. Also, don't be put off by the fact that WINE is an emulator: speeds are near native and for some apps, actually better than running natively under Windows.
Now that you're formatting, it's the perfect time to at least have a play. When partitioning your hard drive, set aside 5 or 10 or 20 gigabytes and install Ubuntu into that partition. It's best to install Linux after Windows, as Windows doesn't play well when installing alongside another operating system. When installing Ubuntu, it will recognise that you have Windows already installed and it will set up a boot loader so that you can decide which OS to boot into.
All in all, there's no harm in trying it. Just be ready to learn a new system. It's all fairly easy to run these days but sometimes you just have to think about what you're trying to do. Which is just the same as if you went to a Mac, for example.
With Linux, there are two major window interfaces: GNOME (which reminds me of a Mac interface) and KDE (which reminds me of a Windows interface). Ubuntu, by default, uses GNOME, though you can install KDE alongside it and just use which ever one you want.
Another distribution that's meant to be good is called SUPER. It's based on OpenSuSE (which is based on SuSE) and it's meant to be pretty easy to get a hang of, too. It's at http://www.opensuse.org/SUPER .
Anyway, give it a shot, and let us know how it turns out... Just remember, though, that if you complain about it, we have the right to call you a "micro$oft luving n00b", OK?