Limited Connectivity, Wired Network, Non Administrator

I work at a company in the UK which is attempting to start rolling out Windows 7 to all computers (early adopters and all that, it's just a lot easier than the current mishmash of OSes we have!). One of the 4 users migrated so far is having an odd issue with her wired network (her network controller is a "Broadcom Netlink Gigabit Ethernet"). She's the only person not from the IT dept or the MD of the company to be moved across, so we set her up as a non-administrator to avoid problematic software etc etc.

Suddenly, 3 days ago, whenever she switched on her computer, the connection would claim "Limited or No Connectivity" (even though she appeared to be connected to the Domain), and there was no Internet access. Having played around with numerous things (driver updates, both from Broadcom and HP - the laptop manufacturer, being the main one), I found the only way to get it working again was to disable and re-enable the network controller. The problem with this is that it required a UAC authorization (even though I'd set UAC to never notify), and that requires a domain administrator password (which is a pain in the wotsit).

Anyway, I figured, reluctantly, that if I set her account up as a local administrator, that at least it shouldn't require a password to reset the device. Rebooted the PC, and suddenly the wired network started working from boot without the need to reset the controller.

My question is - has anyone else had any issues with non-administrators being forced to reset their network controllers to get internet connectivity, and is there a known fix?