XP System and Vista Software Operation Problems

I have a Umax Astra 3400 and Vista Scan 3.75. After installing Windows XP Pro, I reinstalled the software and then downloaded the updated Windows XP USB Scanner driver. I was offered two drivers--one said something like "oem24" and the other said "3400." I chose the "3400." The Device Manager shows everything is OK. However, Vista Scan will not open, and nor does the Scanner Test activate. When I checked the Task Manager, I noticed the software installed under a login name instead of Administrator--does this have anything to do with the problem?
David Knauss