Disconnect your printer. Download and run this patch to completely remove the printer from your computer.

Restart your computer.

Download the latest drivers.

XP Drivers

Vista 32-bit Drivers

All other drivers

Now, if using USB Cable, install the proper drivers, you'll be prompted when to connect your printer.

Also install the latest firmware for the 966 printer.

If using the wireless function, then recommended wireless settings...

Update the firmware in your wireless router. Manufacturer's website, make & Model needed.

Broadcast SSID(You may want to change this to make it easier to connect)

Use WPA security

Mixed b and g mode(n if available)

Use channels 1, 6 or 11. Most devices work better on these channels.

Save and exit. Power everything off for 30 seconds. Power everything back on, wait 30 seconds, now try to connect.

Now this next article gives you a step by step procedure on how to setup your printer.

How Do I Connect a Dell™ Wireless Printer to a Wireless Network

Choose your printer, under it choose your operating system. You'll be redirected to another page, then click on show all steps and it will walk you through the process of setting up your wireless printer. If something is wrong, it help you through the process.

thanks for the help... I  have tried that but still the same results...need to reboot and unplug the printer everytime I am lucky enough to get ONE scan done. 

The printer works fine but the scan problems started happening after I upgraded to vista home premium.

:(

Thanks ! same problem,updating the  firmware did the trick.

You can try re-installing the printer. Discussed below are some of the steps that will help you do this.

• Disconnect your machine and remove it completely from the computer. There is a patch that you can download to do this. Here's the link for that: http://www.dell.com/support/drivers/us/en/04/DriverDetails?driverId=R166243
• Restart your printer then download the correct drivers.
• Install the drivers and wait for the message telling when to connect and power up the printer.

To scan:

• Insert the printer disk that comes with the computer
• Stop it from running.
• Go to "My Computer" then double click on it.
• Check for the drive with the Dell dis, then right click on it, left click explore.
• Check the OCR Folder. There should be an Abbyy Folder in it
• On setup.exe that's in the Abbyy Folder, right click and then left click to run as administrato and to install the OCR program.