My laptop always downloaded at full speed, but suddenly it took 2 hours for 80 MB
At 4.8KB / s no wonder
Oh no
It used to feel like 10mbs
May well be. But download speeds do not depend on the feeling but on the server delivering the data and your line. It's not your line, so it's the other side that's slow.
Restart the download if that doesn't work restart the PC and Internet router