We recently had 3 workstations replaced in our office. The old workstations had MS Office 2003 (we do not have the install disks), the new ones have MS Office 2010. We have a proprietary program that runs on MS Access. The program was developed on and works properly on MS Access 2003. There are features that do not work on MS Access 2010. We spoke to the developer and believe the simplest solution is to load MS 2003 onto the new machines and continue on from there. Can the Access 2010 be downgraded back to 2003 as we do not want to pay for new copies of MS Access 2003?

Simon Jones has described about downgrade

http://social.technet.microsoft.com/Forums/en-US/officeitpro/thread/b696e9fb-115c-4654-a9b4-120d96cf97bf

It may help you.

That may be the easiest solution, but probably not the best. I have access databases that were designed for 2003 that are now fully working on 2010 with some very small changes.

The most important changes that you will need to do is to reference the new DAO libraries in the VB code.
I suspect that the reason some features are not working is because they are calling old libraries that you no longer have on your machine.

Its disappointing that the developer doesn't appear willing to fix the mess that he has created for you due to not future proofing the code....

There is also another way that may help you: There is a Microsoft Access 2003 runtime which should allow you to run access databases without a full access install. This also works if you have 2010 installed.