As for how/why it happened, my first suspicion would be the malware you downloaded corrupted your system. I've seen quite a lot of instances lately where connectivity has been affected although it's usually repairable with LSPFix. From your combofix log it looks like you got infected on April 16 - does this coincide with when the problems started?
You need to make sure you are protected when you are online. To help keep you clean follow the recommendations in Tony's article here:
So how did I get infected in the first place?
Do you require any further assistance or should I close the topic?