Alrighty, there are a few different things going wrong here. The version of Illustrator I'm using is CS3 on Windows. One of my issues is that when I'm using the selection tool, it won't select an object if I simply click; if I want to move an object or simply select it to re-scale it, I have to click and drag my mouse over it. This makes my life difficult, as it's a serious pain to select objects, and it's extremely annoying.
Another issue I'm experiencing is difficulty duplicating objects. Alt-Drag isn't working on objects; if I want to duplicate an object, I have to hold alt and use the arrow keys on my keyboard. While I've been able to use the arrows to work around this problem, it is both concerning and irritating in equal measure.
I realize this is an older version of Illustrator, but I know people who also use cs3 as well who do not experience these issues. I've tried restarting the program, restarting my computer, and reverting my user settings to default--none of which has been even remotely effective. I have attempted to scroll through forums and advice blogs to obtain help that way, but my efforts have been in vain; no one seems to know how to fix it. Help would be lovely.