Cursor-related problem

I was wondering if someone could help me with this. We had a Charter technician out here, concerning our Internet connection, and he fiddled with some things on my computer. I don't know what he did since I removed myself from my room, being "uncomfortable" around strangers and all.
Anyway, you know how, when you rest your cursor on something (like a link), information appears beside your cursor? That's my problem. If I rest it anywhere, the info stuff appears. However, if there's nothing there, just a small box appears, smaller than my cursor. If that wasn't annoying enough, if my cursor rests anywhere that has nothing, but had picked up information elsewhere (like "Mr. Green" from the green smiley face), it shows that instead of nothing.
While the other changes that were made were minor and easy to fix, I'm not exactly sure where to look if I want to fix this problem. Would it be in Windows, or my browser? The problem only seems happen within the browser window.
Anyway, you know how, when you rest your cursor on something (like a link), information appears beside your cursor? That's my problem. If I rest it anywhere, the info stuff appears. However, if there's nothing there, just a small box appears, smaller than my cursor. If that wasn't annoying enough, if my cursor rests anywhere that has nothing, but had picked up information elsewhere (like "Mr. Green" from the green smiley face), it shows that instead of nothing.
While the other changes that were made were minor and easy to fix, I'm not exactly sure where to look if I want to fix this problem. Would it be in Windows, or my browser? The problem only seems happen within the browser window.