I would start with downloading the latest driver for the camera you have.
While you are at the Emprex website, you should click Support / FAQ.
If that does not solve your problem, on the Emprex website.....click..... Contact US / Service.
I run Windows 98SE and a Emprex 5.1mp camera. On day one I successfully installed the camera driver (as required for Win 98 users)and Ulead Photo Explorer from the provided CD-Rom. I viewed my photos by going to My Computer and choosing the Drive created for the camera. Don't remember the exact "label" on that. Everything was fine. Now on day two, the Drive I used yesterday is gone!. I've tried uninstalling and reinstalling. I get good messages such as ..building driver information base and all the InstallShield Wizards run fully through to Restart Your Computer to Finish. I've been doing and redoing this process for 3 hours now to no avail. What am I missing here? My USB cable is still plugged tight. The camera is on when I connect. Puzzled in Texas.