Download cuts out after few seconds..

Hey,

So lately I have been having some issues with my router or something, first I couldn't even connect the thing to the internet, now every time I try to download something, like a youtube clip, patch for a game or even a tiny download the speed seems to crap out and then slow to absolutely nothing after just 2 or 3 seconds.. also sometimes I can't even connect to my router with 192.168.2.1, the page is just blank, half to disconnect router and reconnect..

Some days I can't even download a website without having to constantly refresh the page..

For a youtube video if I just keep refreshing the page it downloads a part at a time till it gets the entire thing.. Is this an ISP problem or something to do with my router? any ideas how to fix?

My internet speed is around 15 MB/s, before the download quits the speed is always fast..

Thanks for help.