After using the Ndless 2.1.0 Installer on my TI-Nspire CAS Touchpad (with OS 2.1.0 installed) for quite a while, I had recently encountered an error in which the calculator crashed immediately after running ndless . After a number of days without any Ndless version installing correctly, I had decided to re-install the Operating System, BAD IDEA. After attempting this, old OS has become unusable and reinstalling, no matter how many times, simply fails; the only message which appears is the standard "Operating system not found. Install OS now," .

What should I do, Omnimaga? Is there a way to reformat my calc to reinstall OS 2.1.0 successfully; or will I be forced to send my calc away for repair? Is there a way to fix this at home with the RS port on the bottom of the calc? Will TI even accept the calc, let alone refrain from installing the new OS 3.0 on it?

One positive I may add is in the form of the TI-Nspire STudent Software. I had noticed that by opening the program, I was able to view the calc's contents in the My Files/handheld tab, reguardless of the state of the OS. One file in particular, however, seems to be undeletable, being a glitchy "Program Files" folder with a further glitched 0kB "mviewer.tns" inside.
Would this be the root of the problem? When I had opened the folder on the Calc prior to the OS installation, I was able to "delete" the folder, but it would reappear. Deleting it after the attempted installation on the PC Student Software results in an error only. Is this fammiliar in any way to your own calcs?

tl;dr: As stated earlier, I have no OS installed on my calculator, and reinstallation is apparently (due to a corrupt file?) impossible. What should or can I do?

Thank you, whoever has bothered to read this post (regardless of capitalisation or overuse of exclamation points in the title).