>I have a problem with windows disconnecting USB and other non-internal drives regularly, up to the point of diskdrive letter being "gone", then most of the time reconnecting. Sometimes I am asked to format the drive (hiccup in chained drives), no need, data is still there...

Are they connected directly to the MB or through hubs? (Even front side connectors may be hubs), Check Devicemanager, it lists the connection / hub chain.
Plug / unplug all internal connectors that may be involved. Remove the dust out of the comp.
Is this problem on all USB sockets?
Power supply of hubs may be weak, and passive USB hubs (sockets on keyboards!) may not provide enough power. Power savin monitors may power internal hubs down
Problem is on other comps with same device too?

Reinstall windows
Replace MB

And the USB drive simply goes dirty when disconnected the wrong way, so the OS isn't trusting the directory (...) any more. That's why an USB should not be be hot-unplugged (as your fail does)