[dba-Tech] Suddenly second monitor not recognized

[Arthur Fuller]

I have a Dell Inspiron laptop which until 2 days ago performed
magnificently. Then it suddenly lost track of a file in the boot directory
that prevented it from booting at all. I fought valiantly and initially
thought I had solved it, but alas, no. So I renewed the battle on the
second day and this time emerged victorious. But not quite. The laptop
boots just fine again, into the Windows 10 Preview, but now it's lost track
of the second monitor. I double-checked the monitor itself by swapping it
into my ancient tower machine, and there it works fine. But the laptop
cannot see it. I've powered it down, reconnected it, powered it back up,
and still no dice.

I guess I can suffer through this one-monitor hell, but it was a lot more
fun with a pair, the secondary being a nice Acer 22". I miss it.

Any suggestions? Advice on how to make Win10 realize that a second monitor
is attached? The Detect button didn't succeed.

-- 
Arthur