Ubuntu XP dual boot comparison & changes

My original OS is XP, I finally installed Ubuntu on its own partition.
Ubuntu looks fine on a few trials, except that:
1. Documents saved in Ubuntu cannot be opened by XP, although all my documents from XP can be opened by Ubuntu. That limits my continuation of Ubuntu- If there are reasonable solutions available I have not yet found them. Help anyone?

2. Yes, I play games. Right now, Freecell. Using XP, I am at 4430, going up serially. (I have no solution for 1941). Ubuntu did not allow me to choose a number of my choosing. This limitation may apply to other items.

3. I must have XP as a dual boot, since I cooperate with my grandson, and my other younger grandchildren use my computer when they -often-come around.

4. What are the differences between Ubuntu, Kubuntu, etc. As a long-time Windows user, I like the GUI system, though I use the command when necessary. Preferences anyone?
Thanks
ezrab

4. What are the differences between Ubuntu, Kubuntu, etc.

"Kubuntu" has what is called a "KDE" desktop, "Ubuntu" is a Gnome desktop.
Just a matter of style and personal taste. Ubuntu is the more popular of the two. If you'd like to try a KDE desktop, you would be better off installing "OpenSUSE"
http://en.opensuse.org/Welcome_to_openSUSE.org

About Ubuntu documents not opened by Windows: All of Open Office documents can be saved as Microsoft documents. If that doesn't work, save your files as PDFs, which can be read in Adobe's Acrobat Reader.

I have Ubuntu and SUSE, and I really like Ubuntu because it has an easy interface, and it is quick and easy to install...it's usually up and running in 15 minutes.

What do you mean Windows can't open documents saved from Ubuntu? If you don't save them to a partition that Windows can read you won't even be able to see them. That may be your problem.

For a good gnome based distro that won't crap out on you, go with Debian, for KDE go with OpenSUSE or Mandriva. Try to avoid Ubuntu unless you don't mind tinkering.