In preparation for my post-Christmas project, I wanted to make sure my recording rig was working ok.

Previously, I've been running my FF 800 with XP and it's been very stable and happy for a couple of years. But I'm an occasional user, so it's been a few months since I recorded anything.
I upgraded to the latest drivers for XP (2.9992), and as advised upgraded the firmware to 2.77, since then I've had nothing but grief.
It's a long story, but for a time I wondered if the FF800 was broken, but (at some pain), I checked an old laptop that had a working configuration and confirmed that XP SP3 with driver version 2.42 and firmware 2.77 was stable.
On my production system, XP3, now with driver 2.9992 and firmware 2.77, nothing works. Various startup combinations cause blue screens. Nothing is predictable.
For example, sometimes, if I power on the FF800 before the PC, a firewire connection will be made. But then, when starting "Fireface Settings" from the systray, it appears that explorer.exe will stall. The settings dialogue will never appear. This is the most common condition.
When I start the FF800 after windows startup and logon, mostly it will ignore the device. Sometimes it'll see it properly, but still, the Fireface Settings dialogue will not render and simply trying to start it makes the system unstable.

This is awful.
Any suggestions would be appreciated. In particular, what is the recommended driver combination for XP SP3?

Thanks & regards