EDIT: The first part of this is WRONG! Please see my edit at the end. I've just fixed this on my laptop having had exactly these problems on Win7 home premium on my Dell Studio SXPS16. The XP partition on the laptop, and other machines, had no problems
accessing my NAS devices, but the Dell supplied Win7 Home Premium, while it could see them, couldn't drill down without losing the connections. Tried ALL the previous suggestions on this and other threads, mapping the drive in a DOS box, addressing it via
its IP address etc etc.
I checked the Intel site, and found theres an 'update' there for the 5100 wireless card series dated 7th Jan 2010. The current driver supplied by Dell/Microsoft for the 5100 adaptor is dated Sep 2009. I deinstalled the adaptor in device manager (which I found
necessary to do to allow the Intel software to actually do the installation. ) When the installer had run (it wanted a reboot), the driver was one dated MARCH 2009, version 12 rather than 13! And now the shares all work and I can map drives from Win 7 and
work with the data on the NASs.
Prior to this I'd done several virgin Win 7 installations on this machine to see if I could see if there was anything odd about my installation.
Clearly Intel messed up the version of the driver that's on the MS win 7 disk and Dells current download site, and from comments here, there may be other wireless network adaptors with the same issues
Here's the link on the Intel site to the driver set that worked for me, but do deinstall the adaptor in device manager , before you do the installation since otherwise it doesn't seem to actually run and the driver is not downgraded:
http://downloadcenter.intel.com/Detail\_Desc.aspx?agr=Y&ProdId=3062&DwnldID=18240&lang=eng.
EDIT: I wrote this after a long night attempting to get this going again. But it's a load of nonsense I'm afraid. It's NOT the laptop card driver, but it IS as was suggested by Gustplus above, the router that the system normally connects to. I have 2 wireless
repeaters in my house, and accidentally forcing a connection to the other one, a Buffalo Airstation, is what makes the SMB work from Win7. The Speedtouch 585 I use for wireless and my ADSL connection is the culprit when running WIn7's SMB over wireless from
the laptop. Trouble is , I don't want to update the firmware since I'm running the last versionof the 585 f/w that was hackable to allow forcing the SNR for optimum ADSL speed. So I shall just have to ensure that the Win 7 laptop only connects to the Airstation.
Very wierd, and even wierder when the Speedtouch has no problem connecting the same laptop to the NASs when I am running XP on it...
Incidentally, this issue only affects SMB. There is no problem with anything else running tcpip from the Win7 laptop into the Speedtouch.