After 2 years of usage, my beloved HTC Desire started acting. It was losing power just moving it a little (for example pulling the phone out of my bag or pocket).
I thought that’s it. Time to move on.
I browsed the HTC forums hoping to find out that some upgrade or some virus triggers this behaviour: no luck on the forums.
Ultimately, a buddy of mine who does tech support, reminded me the basic rule of checking the hardware first (or, in his words, “is the computer power cord plugged in, madam?”).
He was right!
There is nothing wrong with the software.
The problem is with the battery getting loose (perfectly reasonable, after many drops on concrete and other hard surfaces).
Just tighten-in the battery by squeezing in a piece of paper, like in the picture below. It worked for me!