Hi Digerati,
Sorry I've cross threaded a little and answered some of your points in my thread in the Win 7 Forum.
Yes I downloaded all available Toshiba Drivers for Win 7 64 bit from the Toshiba Archive Support site. All 4 of them. The rest came from Microsoft, Intel or Realtek.
The machine had the problem before I restored Vista 32 bit which was running very slow and flaky, often hanging. Now I cannot detect any issues with Vista either on SFC scannow, disc check, Surt tool or device manager - all devices working properly (when present). The audio controller is not shown in Device Manager when booting up cold and the sound icon showing a red cross in the sys tray.
I created a separate partition onto which I have installed Win 7 64 bit. This suffers the same cold starting problem. I don't think these two systems are sharing any drivers, because they are on separate partitions on the hard drive? The Win 7 installation is now running without any reported faults on CheckSUR.
I like the idea that a mechanical connection somewhere is not making good contact. Where to start looking is the issue?
The external sound card you flagged up looks cool. If all else fails......
Many Thanks
Andy