I am having a similar issue after upgrading to Windows 7 Professional 64-bit from Vista home premium 64-bit.
I tried flashing the BIOS using the most up to date I could find on acer's website, no difference. Not that I had any inclination that it would make a difference but I tried the new video driver
: nothing. I've also installed a newer driver for my Zonet wireless USB adapter (ZEW2500P)...still no dice. I have tried another wireless adapter, same problem. I also uninstalled any windows updates that may have installed since loading the OS and I have had the problem since.
I notice that it tends to coincide with when I download data at a high speed (1-2MB/s). After a number of minutes at that speed the networking portions of the computer will just lock up completely and no websites or other internet data can be accessed. I can't load the network portions of the control panel or otherwise view anything about the wireless adapter. However, left to its own the problem will arise after a certain time passes. It is a debilitating problem because when it strikes it prevents windows from shutting down (it will just hang at the "shutting down" screen...I left it like that for half an hour). I don't know what else to do.
Anyone have any suggestions? Did you resolve the problem, simmenthal??