Windows 7 network hangs, works ok in safe mode

My portable is a Targa Traveller 826T with a AMD Turion64 1.8 GHz, 2GB RAM with Realtek RTL8139/810x Family Fast Ethernet NIC and Intel PRO/Wireless 2915ABG.
It worked well under all 32 and 64 bit versions of Windows XP and Vista.
The problems started with the release of Vista SP1. And exactly the same happens with 32 and 64 bit versions of all candidates of Windows 7 after a clean install.
The problem is this:
As long as there is no lan cable connected and wireless is switched off with the hardware switch on the pc everything works ok. But as soon as you plug in the lan cable and/or switch on wireless and network traffic starts the pc totally locks. Powering off is the only option.
In safe mode with network connection however all works fine.
I disabled all services with MSCONFIG but the problem stays.
No other programs are installed, it is a clean install. It seems to me like a buffer overflow somewhere.
When I had this issue with Vista SP1 I contacted Microsoft for a solution. They just said I had to contact the manufacturer for updated drivers.
But now with Windows 7 all drivers are from the install DVD so Microsoft put them on it.
Uninstalling the NIC and/or wireless drivers does not help.
- What else can I try to solve this?
- Can I somewhere find what is activated in safe mode and normal mode to find the problem?
- If something is causing problems after a software update is the hardware then to blame?

Any suggestion is welcome!

Hi, I've got the same laptop as described. I found your solution here, and downloaded the old bios here. Thank you so much for posting it!

I've found your solution for this problem here: Windows 7 network hangs, works fine in safe mode and it worked for me as well. Thank you so much!