I was wondering if anyone knows if I can install and run matcad11 or 14 on my system.
Mathcad does not have a version for Ubuntu, but Wine is a program that makes it possible to run many Windows programs on Ubuntu. You can install Wine through the Ubuntu Software Center. (By the way, feel free to ask if you need help getting things set up in Wine.) Mathcad 11 appears to work pretty well through Wine (see here); animations may not work, though. Mathcad 14 might work well through wine (see here). Either version appears to need some tweaking to get running.
If it won't work through Wine (or its versions like the commercially-supported CrossOver Linux), then I don't know of another way to get that specific program to work in Ubuntu.
There may, however, be acceptable replacements on Ubuntu. This blog post refers to SMath Studio as a "free Mathcad alternative for Windows, Linux and Windows Mobile". It doesn't look like it is packaged for Ubuntu, but you can install it by following these instructions. I've included a screenshot of SMath Studio below.
is it a windows program that runs on windows XP? If it is, try running it on wine (software center > wine.) It may require a little more configuration, and in such a case, you can comment on my answer and I'll see what I can do to help =)
Optionally you can see if it is supported by playonlinux (an interface for managing wine), which should make life MUCH easier.