a message appeared on my laptop saying ' low on memory ' close programs, what does this mean?

[Nick]

memory as in ram, not storage, when you have low memory things tend to crash, it can't keep up. this is why a lot of computers tend to have 8gb of ram, it's quite plenty to run a lot of programs at once. too many programs, too many things to handle, it may crash some programs just to keep up, that's why it tells you to close them yourself to prevent loss of data which may occur if it decides to close it on it's own.

there's no need to be alarmed, it happens sometimes, you may just have not a lot of ram, you can upgrade that easily if this is a problem to you, it's even easy on laptops, and relatively cheap, although prices have gone up.