weird wireless problem

Hey everyone
I'm having some weird problems with my wireless network lately.
Some general info:
Comcast ISP
Linksys WRT54GS v5 router
two wireless desktop computers

I recently installed Vista onto one of my desktops, and popped in my network adapter a Linksys WUSB54GC. Of course nothing happened and it took me hours just to get Vista to recognize and properly set up the adapter. I finally got thing working and the computer onto the internet.

Now my internet connection randomly drops when it is being taxed a lot. I.e. when downloading a 5gb file or streaming video off of netflix for three hours. My internet connection will randomly drop, and then Vista won't be able to find the network again unless I restart.. and it ONLY does this when I stream video for a while or try to download big files. Just normal browsing does not cause the disconnect.

I'm thinking bad driver (or is it PITA OS?) but I'm assuming you downloaded the Vista Driver from Linksys. I was reading that Comcast was not going to do anything about limiting subscribers from downloading large files via some programs out there. I'm at a loss here. Maybe change USB ports if possible. maybe that one is having some issues when you get cranking on the internet.

Also make sure that the computer isnt turning off the wifi as part of some power saving mode.. I've had that issue many times.

In the device mangler, check the resources tab on the wifi adaptor to check if it's set to "turn off this device to save power".

Yea it isn't my ISP because my other desktop with a different linksys adapter and XP is able to download the same large file no problem..

I've checked the power saving mode too. Until I fix this problem I can't download any of my purchased games off of direct2drive!!

UPDATE: I mapped the shared folder as a network drive (Z:), and then tried using the command prompt to copy over the file. Its exact size is 4.91gb. Still no luck.. I recieve the following error:
The specified network name is no longer available.