Acquiring Network Address

Hi, I have a home network with various wired and wireless static and dhcp clients. One of my XP2 laptops was part of this happy network. Recently, it hangs on "acquiring network address". It has two NICs, one wired , one wirless. It occurs on BOTH (and also on a USB wireless adaptor that I dabbled around with). (All tests share the wireless router as the common component.) After a while, the network stack rolls over to assign 168.xxx.xxx.xxx, ie the auto-configuration IP (and I get "limited connectivity", which is an understatement). I can reconfigure the network stack for static IP (valid subnet, gateway, etc) and I still CANNOT access to my network. Ping etc all fails. The usual suspect network services are all running: Location Awareness, DHCP Client, RPC, ... I have no MAC filtering on the router. (I use WAP, but that seems hardly the issue since the wireless NIC actually finds the carrier, and not even the wired connection works.)

Problem I have is that the laptop has some corporate s/w on it that I cannot afford to lose so that I'd rather not re-install the wretched OS.

This probably just confuses: In despair, I rolled the OS back through the System Restore functionality. After that was completed, the laptop WOULD hook up to the network ONCE only. After the laptop rewoke from hybernation, we were back to "acquiring network address"...

I have read hundreds of threads on this problem and I hope you can see from my description that I tried all the usual remedies to no avail. I hope that someone out there has some further inspirations... Thx.