Yes, sometimes new programs have problems... I installed Photoshop CS3 on my new PC but it was very slow and kept crashing with no warning ...
pretty much the same scenario you had with GIMP. So I went back to Photoshop 7, and I'm very, very happy with it. It's very fast and stable, and has mostly the same features.
When you get used to it, Photoshop is much easier to use than Paint, and you can do a lot more!