I am using windows 7. No haven't used symbolic previously in this PC nor anywhere
Ok, that's a very important detail. Were you able to install the package without Python? I thought it gives an error. (Colin, is that normal?)
Symbolic package is an interface wrapper to Python/Sympy. Pleases follow the directions here:
The simplest method is to use the bundled package. download it and do a manual package install. (pkg install <filename>)
If you want a separate python install on your machine, follow the directions for either Anaconda or Python.