This free program for Windows XP lets you create a virtual CD drive on your hard disk. Some visitors to the site have confirmed that it works with Windows 2000 too (but this is not stated in Microsoft"s official readme).
For anyone unfamiliar with the terms "virtual CD" or "CD emulator", they mean that you can copy the entire contents of a CD-ROM to your hard disk and run the programs or access the files without the need for the original CD. This can make files more accessible, faster and more convenient. Given the speed and size of today"s hard drives, you could easily fit a number of CDs onto your hard drive without noticing the difference. Assuming you had 30 full CDs, these would take around 20GB on a hard drive and all will be accessible after a few clicks of a mouse.