I am not sure whether this is a hardware problem or not. A few weeks ago I installed an external hard drive (drive L. At the time A window popped up asking me whether I wanted to format the disk in drive K:. I checked and I had no drive K: While the window was open I couldn't do anything and clicking cancel had no effect. I solved the problem by booting from my recovery flash drive and restoring the computer to an earlier date. That was a couple of weeks ago and the problem has returned again. This time restoring from the recovery flash drive hasn't worked. I can reboot from the recovery flash drive successfully but if I reboot normally the problem reappears.
How can I fix this problem?