Problems after vista update...

I have Vista basic on my laptop and after an update, my external harddrives are no longer working. I can see them in the device manager but they have the yellow triangle and the message "Windows cannot load the device drivers for this hardware. The driver may be corrupt or missing. (code39)"
When I try to update the drivers it says that "the best driver software for your device is already installed. Windows has determined the driver software for your device is up to date."

At the same time this happened, I was not able to open Zune software due to .NET Framework missing and now I can't install .NET Framework 3.5
or any Vista updates.

HELP Please :confused