I had OS9 on my iMac, and used the supplied-CD to upgrade to 10.0.x. Lots of issues now, and the forums tell me 10.0 is a joke. How can I upgrade to 10.3 or 10.4? Every time I download anything through IE a .dmg file is created, and it can't be mounted by 10.0. I'm goin' spare over this.