How many bytes does it manage to download?

smells like an antivirus software issue.... any messages in the logs of those applications?

What are u using for antivir, firewall, spamkiller?

Have u tried disconnecting from the internet and disabling the security software one by one?

Let us know the device id (in Agent Prefs page right hand bottom) and last estim.time of contact with servers.

cheers

PS... my antivir has shown 3 /4 daily updates of the libraries since about 4 / 5 days, so to me that piece is a usual suspect on my list.

DEP is fine to switch on, as long as you set up exceptions for the Science and the UD.exe. Here's an article on the matter by WCG staff: Another Reason for a Paused Agent