If you are on Windows 7 and do NOT have 64 bit. Please go to the Toolbar Page and after you download it. It has links to EVERY Version of Quake plus online Servers too! I own it and have complete assurance in its awesomeness!
Now if you have 64 bit and are on XP or Windows 7. Listen to me. Any Quake 1,2 and 3 etc came in 16 bit and 32 bit only. What am I saying? It never was nor yet in 2012 has never been a 64bit Friendly World.
I own a 64bit machine and made the BEST decision ever in my life. I switched to a 32 bit (x86) OS (in my case XP) Now my machine runs MUCH MUCH Faster and most importantly ANY Software runs on it! You can use the SAME key if your on Windows 7 plus you should have the 32 bit DVD in the same case. If this is not the case then , download a 32 bit online and install it. Best Decision You've made next to suing Microsoft!