What I want to learn about computers

Going though the term of CPS100, I think I learned a lot about computers,
What I want to learn now is, how to use excel, since when Iwas looking for a new part time job,
Inoticed that who can use excel and word are receiving higher payment.
I also want to know more about using design programs. i am now using GIMP,
but I want to know what softs are there for designing and I want to know more deeply about GIMP. I think it is profittable to know how to solve problems when we getr vilus in our computers, or how to solve when we had downloaded a program which had a problem.