If you have IE on it's absolute highest security settings it will not be able to download files. Which security settings are you using for it? I would suggest you might like to try firefox or chrome for browsing and file downloading instead, but problems with IE (as in, if this isn't just a consequence of the settings IE is running under)can indicate something wrong with other parts of the system so it is important to try and find the cause and make sure it isn't something which is going to cause other problems.
You mention you cleaned the registry, this is generally a very dangerous thing to do. You might have come off alright this time but you probably shouldn't clean the registry again. Registry cleaning doesn't usually improve performance or any other part of a computer system. CCleaner is good for all the other features it offers ( it's temp file cleaning feature is helpful for keeping things running fast, it's useful to run it manually every week or so, it's startup disabling/enabling feature can be helpful as well), but it's registry cleaner features should not be used.
I suggest it might be helpful to others here if you run minitoolbox, as downloaded from this page http://www.bleepingcomputer.com/download/minitoolbox/
with the options for: "Report IE Proxy Settings", "Report FF Proxy Settings", "List content of Hosts", "List IP configuration", "List Winsock Entries", "List last 10 Event Viewer logs", "List Installed Programs", "List Users Partitions and Memory size" all ticked. DO NOT tick any of the other options. The log produced will give information about your system which can help members of this forums recognise ptoential causes of your problems.
For now don't change any settings on your system , and don't clear any temp files for a little while, if you do you might end up losing logs which might be helpful to people in trying to diagnose the cause of this. Cleaning temp files is usually useful, but when you are trying to find the cause of system problems it can be useful to let them stay (for a while atleast) as they include things which might give clues as to what might be (or have been) wrong.
Edited by rp88, 12 June 2015 - 04:31 PM.
Back on this site, for a while anyway, been so busy the last year.
My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB