There is no specific instruction for this issue unless we consider "reload the OS" which most folk want to avoid.
Keep writing and use Grif's advice which has you get the tools needed from another PC.
The most common issues I run into are malware and other things like limited user accounts and folk that set the security setting on everything to HIGH. Not much works on that setting.
I have a dell inspiron and am using windows 7 home edition. . I cannot download any type of files. I attempt to download a file and get the download dialogue box but underneath the file name it says canclled and when i try to download anyway there are no files to be found. I use Mozilla as my default browser. I also tried downloading in IE, but that to did not work either. I am novice at repair, so specific instruction would be appreciated.