"Few" means "not to much". Saying "few students" you mean that there are not many students who like remote learning and buying a new computer won't be profitable (if you are a teacher, for example). "A few" means "pretty much". Saying that you mean that not to much students like remote learning but still enough (to buy new computer if you are a teacher, for example). The same difference is between little and a little. For example:
I won't buy it because I have little money (to little). Or:
Can you afford this? Yes, I've been shoping for a couple hours but I have still a little money so I'll buy it (a little - still enough).