I have a USB memory key and it doesn’t say how big it is. Is there any way of finding out how much storage it has?

If you look at the USB drive in Windows Explorer you can tell the capacity of the disk by right-clicking on it and choosing Properties.

I bet that was simpler than you expected 😉 It’s always good to know how big a memory key is as the last thing you need is expect to have some space and not find any. A USB key can only take so many adverts for Technical Recruiting Jobs, if you don’t delete any the old ones, you’re not going to find space for the new ones!