I had to do Visual BASIC in my first year of College. It isn't too bad, very simple actually. It really isn't the best language though [it isn't cross-platform, its slow/buggy] and in general it doesn't teach good programming practice (because it is so interactive). Though, for learning programming logic; it's fine, though you'll see a vast difference in complexity when you move onto other languages like C/C++, JAVA, etc..
Computer repair and networking is really handy to have. And it really isn't _that_ hard. With the web you can find guides and help on troubleshooting problems quite easily.
Database design, again, isn't that hard. Though it does depend on the size of the database you're wanting to design and what all features its going to include. Is it going to be a relational dbase? Does it need to have an interface that will require macros etc? What package are you using? Access, MySQL, Oracle? They're all different, though mostly have good documentation.
Good luck.