I wonder if you have acquired some malware/virus ? If you have access to another computer that can burn a dvd/cd for you, you could try this . You would have to have BIOS ( F2 ) on most computers set for boot from cd/dvd first . Make a cd/dvd of or maybe a flash drive ? check this out . How to use Malwarebytes' Anti-Malware to scan and remove malware from your computer
and then check this : It is possible that the infection you are trying to remove will not allow you to download files on the infected computer. If this is the case, then you will need to download the files requested in this guide on another computer and then transfer them to the infected computer. You can transfer the files via a CD/DVD, external drive, or USB flash drive.
Try this and see if malware/virus has the computer infected . Post back results