You'll need to find access to another system somewhere - there's no way you'll get the system repaired without the boot media.
It's also possible that if you cannot get to the diagnostics (F12 before Windows begins loading) that you have a hardware fault - so you may want to call Dell about that possibility in the meantime.
Call Dell and walk through the troubleshooting they request. You are indeed expected to do that (read your terms of sale -- it's a requirement before service is dispatched).
If you cannot get to the diagnostics, you most likely have a hardware fault - the warranty will cover it, but it all starts with calling Dell support and walking through basic troubleshooting with the technician.
If you don't want to do that, it's your option - you can take the system to your school's IT staff for troubleshooting.
The problem isn't attitude - you just can't solve problems with a magic wand. At a minimum, you're going to need an OS reinstall - and to do that you'll need the recovery media, which you'll need to make, one way or another. There is no magic way to solve the problem - and since the hardware is very much suspect at this point, you'll need to start by contacting Dell support to open a technical support incident.