For some reason, at random times when Inkscape is opened, this tool doesn't do anything. The mouse doesn't change with it and nothing can be clicked or moved. This problem goes away on its own but is there a workaround?

I haven't heard of such a bug, but you might want to search Launchpad to find out if one has been reported.

I'm trying to think of reasons why this might happen otherwise. And I've noticed that if my system is bogged down for some reason (usually the image I'm working on takes up a lot of RAM and/or cpu), then I can't do anything until the last function I clicked has completed. Once it has finished, my cpu use goes back down, and I can continue working.

So when this happens that you can't use the select tool, can you use other tools? Or is everything else working properly, while it's just the select tool that you can't access?

Just a thought

Well I think it has nothing to do with speed. I mean, yes my computer is slow, but that's not the reason. Other tools work fine. I can draw a square. That doesn't mean I can move it. Even when I close the program and open it again, the problem persists. It could just be me. Does anyone else get that error where the program refuses to minimize?