My boss’ computer had a bad case of the Mondays this week. It took forever to come out of power saving mode, and then when it finally did, it was mostly unresponsive. He couldn’t log in, and the system didn’t even recognize his smartcard reader. The usual fix for a smartcard reader that won’t read and whose light doesn’t blink or come on is to unplug the card reader, wait a few seconds or a minute, and plug it back in, but even that didn’t help this time. Nor did plugging in a known-working reader.
The machine did respond to ctrl-alt-del, and the shutdown options weren’t disabled. Fortunately. So I did a full shutdown, which it did, under protest.
The hard drive chugged for a while, and then the power light stayed on for what seemed like forever even after all other signs of life disappeared. I waited, and eventually that faded too. Then I pulled the plug from the back of the machine, waited a good 20 seconds, then plugged that in and powered it on. The light on the card reader lit up as soon as the HP logo appeared, which was good. Windows booted pretty quickly, taking 30-45 seconds or so. And then he was able to log in.
It’s good for desktop PCs to be unplugged and just sit, with no power, for a little while every so often. I learned that trick a good 20 years ago. In those days, we believed that an errant program would sometimes corrupt an area of memory used by something else, and shutting down hard for a few seconds cleared the memory and fixed the problem. Modern versions of Windows police what areas of memory a program can write to, but there are other ways for memory to get corrupted too, such as cosmic radiation.
DRAM loses its contents within a few seconds of losing power. Waiting 20 seconds gives the capacitors on the motherboard enough time to discharge, which ensures that the memory did indeed lose power. Then when you power back on, everything gets a chance to load anew, and the machine should be fine for a few months.