You know more about Xubuntu at this point than I do, so I can't help you with whether it's a good idea or not
Hopefully that works. Sorry Ubuntu didn't work out well :\
I was going to mention Fedora. It's not as user friendly as Ubuntu but if you've gotten this far and feel comfortable continuing to plow ahead you'll have no problem with Fedora. But their minimum system requirements are about the same :\
Sucks. I didn't realize those OS's had grown up so much.
But there is another option... Debian. Debian is significantly less user friendly. I really like Debian, if I were to install a linux I'd go with Debian above all the others (including Ubuntu and Fedora) but I'm far from an expert on it. It's among the more popular linux distros among those that graduate past the entry systems of fedora and ubuntu. Debian's a true step into the world of linux. It's minimum system requirements are a Penteum 4 1 ghz and 256mb of ram.
3.4.*Meeting Minimum Hardware Requirements
you can read more about it at debian.org
There's tons of good information about how to do things in debian on google, and who knows - maybe you'd become a true linux guy. Most people that venture that deep into linux never go back... ever. I'm always willing to help but you'd pass me in knowledge on it pretty quickly. Not sure how many linux people we have here, by that i mean true linux people, you'll likely have to find other resources.
At the end of the day these are all linux distros. a group of people took a core operating system and tweaked it enough to build their own custom platform on top of it. but fundamentally most of the things you'd want to use are available generically for linux.
it's an option. it's not daunting. it's a question of how much you want to invest in learning a new OS vs dealing with your computer vs buying a new one.
If you're really adventurous you could try Mint. It's not as hard as debian but its not nearly as polished as the others. I couldn't even get it to work last time I tried but I had a pretty wild and unsupported setup when i was messing with it.
Pay special attentions to install instructions for linux if you're trying to keep your windows install. Don't venture into this without backing up your system really well - you might accidentally destroy it (you can rebuild it, but you might lose data, you wont permanently break your computer though.) So make sure you read them 3 times then ask your questions here if you can't find answers elsewhere.
I don't really feel like walking you through how to rebuild your master boot record even though it's not hard :\