Hi cvbt,

You can do this by creating a new hidden preference.

• Type about:config into the location bar and press enter
• Accept the warning message that appears, you will be taken to a list of preferences
• Right-click somewhere in the list and select "New > String"
• For the name of the preference type browser.cache.disk.parent_directory
• For its value type the path to where you want to store the cache
• Next locate the preference browser.cache.disk.enable, it must be set to true, if it is not, double-click on it to change its value

For more information on this see this article
Hope that helped. Please report back!

By default, your cache is on a different path from your main settings folder.

Main settings folder is under:

C:\Users\username\AppData\Roaming\Mozilla\Firefox\Profiles\

Cache folder is under:

C:\Users\username\AppData\Local\Mozilla\Firefox\Profiles\

(The above assumes Windows Vista or later)

Thanks alco. It created a set of directories where I specified. The old cache directory still exists and it is still very big. Any suggestions? Hmmmm; I think I need to check if this is the directory that I keep my FireFox preferences in. I have just upgraded to Win7 and reinstalled FF. This may be an inactive Cache Directory. Yup, that was it. Thanks everyone. I've set up a new clean profile and deleted the old information. It's like riding a brand new bicycle. Happy Thai New Year.

You can delete the old cache folder and then Firefox shouldn't be using it.
Make sure that the new cache folder(s) exist.