I don't know much about QBasic, I haven't done BASIC programming for years now... But I have some ideas (Hope it's not too late)
Do you want to make the game using just text output with maybe some simple graphics? Or do you want a modern GUI format game?
If you want a modern GUI format game, then there may be some modules which you could download which let you make GUIs in Qbasic, then you could use
'event-driven-programming' so that you could use the mouse to do whatever you wanted.
I know there are loads of GUI frameworks for Turbo Pascal people have made (Usually in C/C++) which you can download, so like I said, maybe you could
find ones for QBasic - Only problem is... As QBasic wasn't exactly a great programming language (for 1 it was a variant of BASIC, and 2 - it was
'made' by bill gates, lol)
Developers may not of wanted to make modules for it.
It's worth a look anyway. I'm not too sure how you would trigger events using the mouse in a text only based format game - not even sure it's
possible. (But I am prepared to be stand corrected).
It is a mystery why your school is using QBasic... As it is such a bad programming language, in terms of style and structure. I would of thought you
would of used Pascal (as most schools seem to use Pascal, lol).
Is this a introductory programming course your doing? If so... Your lucky to even be able to do this stuff. I am assuming you are in the US, or any
other country apart from UK, lol. As in UK students are not even tought what a damn Ooperating System is, let alone programming, lol. Thats the
schools I used to go to anyway

(Secondary [11+] schools I am talking about here)
Anyway, I hope this is of a slight help. I am just sorry that I couldn't be more helpful.