Why is it when I switch my pc on first thing at work the number lock is always off?

Why, when the numbers are on a separate keypad, do we need a Num Lock at all?

Older versions of Windows 10 did this. Are you using the latest build?

Usually an option in the BIOS settings for whether to enable num lock on boot.

Could be worse, mine seems to want to switch on at random (I presume it’s some software’s default). Which is really bloody irritating when you’re trying to do something in CAD and it starts randomly spinning (and crashing the graphics card) rather than entering a dimension.

Usually an option in the BIOS settings for whether to enable num lock on boot.

It is, but (annoyingly) W10 overrides it unless you’re using the Creator’s Edition.

https://www.howtogeek.com/244606/how-to-enable-num-lock-automatically-when-your-computer-boots/