Tech: upgrades and compatibility

I have some experience in debugging and fixing problems with tech equipment such as computers.   In any investigation of a problem, it's important to know exactly what things you know to be working correctly, and those that you're not sure about.  So whereas I might use, for example, a wireless mouse on a day-to day basis, I always keep a spare wired mouse that I know to be working, because there are two (extra) points of failure on a wireless mouse: perhaps the wireless connection is not working for some reason, or maybe the batteries (that it necessarily carries since it doesn't get power through the wire,) are flat.    So if I am testing or setting up a PC, I always use a wired mouse and keyboard.

Being in France, I use an AZERTY keyboard on all my PCs, since it makes the special characters like é,à,è, ê etc more easily available, but I have an ancient wired QWERTY keyboard lurking in the cupboard.  This came to my aid recently.

I use a Dell PC for running music software.  It came with a nice wireless keyboard and mouse.  It was configured with an SSD system disk of 128GBytes, and 8GBytes of main memory.  The system disk was too small for the software I want to run, so I upgraded it to a 1TB SSD.  No problems.

I decided to do the same with the memory and upgraded it to 32GB.  Problem.  When the system was doing its Power-On Self Test (POST), I got an error message, to the effect that the memory configuration has been changed, and did I do this on purpose, or do I want to re-seat the memory,  Yes or No?   It's a reasonable question, and probably useful in some circumstances, but the problem is that at this point, Windows is not running, so the Windows drivers for the wireless keyboard are not running either, so the keyboard isn't working.    And since the Dell came with a wireless keyboard only, I had no way of responding to the question.

So my ancient 20-year-old QWERTY wired keyboard came to the rescue.   I plugged it in, typed the response and off we went.   (It's worth noting that the POST software is also programmed for a QWERTY keyboard only)   But if I hadn't had the keyboard I'd have had to beg, borrow or buy one to get past that little hurdle.