Windows 7 - Installation Drive for Updates

Hi out there in the forum!
XP, Vista (x64), and now Win 7 (x64): they all do it the same way: when installing updates (manually downloaded or via automated update), they choose the largest hard drive available for uncompressing the installation files into a folder with a cryptic name (this is not identical with the defined "TEMP" folder!), and delete this folder after the installation process.
Unfortunately in my case this is the network drive (mounted via NDAS as "real" drive) , which means prolonged installation times via LAN, and tedious waiting periods via WLAN.
Win 7 has the tendency to also update hardware drivers. Today it decided to update my ethernet network adapter, cut in the process the connection to the network drive while resetting the adapter - and with doing that had no access any more to the install files on the network drive! No LAN connection until I revived an earlier restore point.
Now (finally) the question: is there any way to tell Win (XP, Vista, 7) which drive to use for these kinds of installations (preferrably a local hard drive of MY choice, and NO, I do not want to disconnect my network drive every time I have to do an update!)?
I have asked this question in many forums / magazines etc, but never got an answer to that. Maybe one of you gurus out there can help me?
Thanks for your time
Bernd from Germany