ChristyNichole, bring up Windows Explorer. Click on the + next to My Computer, then click on the + next to Local Disk (C), then click on the + next to Windows, then click on the Repair folder. Then, click on the file Autoexec.nt . Hold down the Ctrl button and then the letter C on your keyboard (Ctrl-C). This will copy the file. Now, using the mouse click on the system32 folder. Then, hold down the Ctrl button and then the letter V (Ctlr-V). You will then be prompted that the file already exists, do you want to copy over it, click on Yes. You're done. (You might also want to copy Config.nt from \repair to \system32 also).

I now have SimCity 3000 working on xp pro sp2. I am running an AMD64 3000 processor, 1gb dual mem, twin gf6600 sli graphics cards.
The game runs in 32bit colour depth and at 1280 x 1024 resolution. It looks lovely! I havn't needed to change any compatibility settings.

I tried to install in on my AMD64, the installation would start, but when it reached the blue screen it wouldn't go any further, no error message, just stop.

I ended up installing it without a hitch on an old Dell Latitude 400mhz laptop i got, running xp pro sp2. I then installed the BAT patch:
http://simcity3000unlimited.ea.com/us/simexchange/downloads/sc3k_bat/index.phtml

It ran without any problems on the laptop. I then, over the LAN, copied the whole C:\program files\Maxis directory to the AMD64.

I run the game from C:\program files\maxis\simcity 3000\game\sc3.exe

I get 2 error messages when the game loads, and after that it's fine.

Thanks everyone, especially Sampson, for the posts. I went from clicking on the "Install SimCity 3000" button incessantly and getting no reaction from Windows, to having this game installed and running on XP SP2 in about 10 minutes. Freakin' Sweet!