None of those models are supported on Windows 7. The last driver release for them was for Windows Vista.
There's a good chance the Vista driver will work on Windows 7 so try it. If it doesn't work, you still have the option of trying an application called "VueScan" from from here: http://www.hamrick.com/
Try it for free and if it works you will have to buy it if you want to keep using it.
The only other alternative is to buy a new scanner.