"Operation System not found" error message on Inspiron 7000

Hi, After trying to upgrade to Windows 10 from 8.1 on my Inspiron 7000, my Windows install would freeze during the start up process - the Dell logo would appear and the loading icon would stop. I had Linux installed on a separate partition so I went into the BIOS and moved Ubuntu ahead of Windows - this was the mistake. After exiting, I get the error message "Operation System not found". When I start up, I see the options F2 Setup and F12 Boot Options, however I cannot access either - the text will become bolded to show that I have selected it but I always get brought to the same screen which says "Operation System not found". Any ideas on how to proceed? I don't mind losing the files and folders on the device, I just want to be able to use the laptop again. Thanks.