1. Make a new admin user account and re-test.
2. Reset the browsers (google "how to reset chrome")
I've had my laptop around 6 months now and up until a month ago it was completely fine downloading any sized file, however now when I try to download a file from my browser(chrome) it starts downloading then over around a 5 second period the download speed deteriorates until it comes to a stand still, it still says the file is downloading when i try to close chrome however it isn't downloading.
I have tried to also download with Internet explorer 11 and the problem still persists, I do not receive any error message. In my downloads folder it always creates and 'unconfirmed download' file for the file im trying to download.
Any files smaller than 1mb it lets me download but anything bigger it won't allow me to.
I was thinking it could be related to my internet however I have the problem at my home wifi and my university accomodation.
Thanks for any help.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic