Default Sony ADB Interface Driver not being recognised

Hi all ... I am trying to load DoomLord's boot IMG (ready to load a new ROM) and for some reason when I plug into USB (with UP volume) my computer can't recognise the Sony ADB Interface. It recognises the "Sony ADB Interface" as "Found New Hardware" then when I try to select the Sony drivers it says it can't match it and fails when you finish.

I have installed Flashtool and all the drivers, in addition to downloading the latest from the Sony website. I even right click on the .inf files and install them direct but still Windows doesn't want to recognise my phone!

The ADB command prompt waits for a device to be connected, I assume because Windows has not recognised the Sony ADB Interface.

Any ideas? It has all worked previously, when I first rooted the device.

(note, running Windows XP)