This has been a problem with Win7 for a long time and must be a show stopper for businesses. I have tweaked the registry and done everything here:
http://www.tomshardware.com/forum/75-63 ... ssue#t1444
with no luck.
Win7 really blows regarding networking. The neat little home group thing, does only work amongst Win7 boxes.
So CEO's out there: You will have to wait before you migrate to Win7. Its communication skills is nowhere near XP and even Vista.
Win7 is the Win version that does not communicate with Linux servers - that could be potentially expensive for you.