Every driver can be downloaded. Drivers need to be updated regularly as and when they release, so the drivers on the CD become obsolete anyways. Every driver can be found on respective manufacturer's website. nvidia's drivers are on nvidia.com, your motherboard manufactuter should have a website too (asus.com, gigabyte.com, intel.com etc.).. Also, you dont need drivers for processor. Here is a list of drivers that you would need after formatting your PC:
1) Audio drivers
2) Graphics drivers
3) LAN card drivers (not usually, but in rare cases)
If you list down the manufacturers of these, we can point you to the respective websites. Also, please post what Windows are you using, e.g. windows 7 32 bit or 64 bit, windows vista 32 or 64, windows xp 32 or 64. Usually drivers are released in separate executables for different OS. Hope this helps...