Laptop not starting past StartupRepair - NoOSInstalled

Hello - I'm hoping I can find some help with this issue. I have a Dell Inspiron 1545. So, a few months ago, I got mad at my laptop and slammed the screen down. I think it was taking its sweet time shutting down or something. I can't remember. Anyway, the next time I tried to turn it on, it goes into Startup Repair, and then comes up with a screen of errors, namely "StartupRepairOffline", "Autofailover", "NoOSInstalled". I can go into advanced options and go into DOS command (it comes up to the X drive); I was able to successfully pull off stuff I wanted, but I'm thinking I damaged the hard drive. 
I've let this sit for awhile, using my daughters' laptop, but now I want mine back and want to repair it. What should I do first? 
Also, I don't think I have any startup disks or anything like that...

Thank you -