Not that long ago, my Windows XP Home system decided it needed an update, so it downloaded 30MB or 40MB (a real pain in the toliet muscle on a dial-up connection) and then installed it. I think it was Service Pack 1, but I could be wrong.
After it said I needed to reboot to finish the installation, all of my icons disappeared too, but after waiting 15 minutes or so, they all came back by themselves.
If you install SP1 again, try waiting awhile to see if the icons come back by themselves. Give it 15-30 minutes.
If they don't, the heck with it. Do what you did before to remove it, and don't screw with it again until or unless you find out otherwise.