Interesting. I have the opposite experience. I gave my kids a sign-on, told them what their password was, and left the room.
They still boot up to Linux to play some of the games on that box. They know how to use it.
I don't know what distro you used, or when. I know some are more difficult than others ot learn. I happen to use Fedora exclusively, and it seems to just work for everyone in my family.
I had that experience with my grandma just the same with windows or linux, but the lack of problems that are experienced now she'd never go back to windows.
The biggest problems I've had over the past few years have been empty printer cartridges, a loose power cable, and a "I forgot where I saved this file at".
Well, it all depends on the learning curve. Distros like Xandros and Linspire are catered toward the n00b. I've been using both since July 2004...now I mainly use Xandros 3.0 Business Edition. At first I didn't know how to get my modem working, but once I learned how to compile my kernel headers by using the Xandros kernel source, I was off into the stratosphere. These days I rarely use Windows (only time I use Windows is to record TV using my WinTV USB TV tuner and use TMPGEnc DVD Author and DVDshrink and Nero to make video DVDs), but I do have Crossover Office 5.0 Pro so I can use iTunes. Once Linspire open-sources their CNR client, I plan on installing CNR on my Xandros box so I can download and install Lsongs and Lphoto.