FOLDER COLORS

Are you on about the folder icons themselves, or the backgrounds and window colours?

The yellow folder is an icon, not just a blank folder coloured yellow. To change it, you will have to change the icon you associate with File Folders.
To do this, open Windows Explorer -> Tools -> Folder Options -> File Types tab. Scroll down to N/A - File Folders. Click it and then click Advanced -> Change Icon.
The default icon is %windir%\System32\shell32.dll

There are dozens of icons there to choose from. If you have a different icon you want to use (say a Red folder icon) then just change the path to the icon.

But you can't just change the colour. Gotta change the icon.

hope this helps

Look at PowerDesk:

www.ontrack.com/powerdesk/

"In the physical world, you might use different colors of folders or labels to prioritize your paperwork. Now you can apply that idea on your PC. With PowerDesk Pro 5 you can customize and prioritize your file folders with eight distinct colors. "

There is a utility called Rainbow Folders I found on the web, I believe it was Webattack. Anyway, I now have a blue Winnt folder and a Red Temp. folder. Try it out.