If I uninstall it, I can always install it again, right?
Yes, you should be able to. As long as you've got the CD key, you should be able to download it from Steam or re-install from the disc.
As for the system specs, I'm not very knowledgeable about graphics card but the rest looks all right. You're saying you play on minimum settings and still get a low FPS? You clicked "options" in the launcher and turned down all the sliders? Do other games also run slowly on your computer, or is it just Skyrim?