1.try a system restore first..go back as far as you can.
if that works run a complete scan.
2. If you have an installed antivirus and anti malware run a complete scan with all utilities you have. if it finds anything then you should be able to get back on.
-if it does find something and it deletes or quarantines it and then it operates correctly be sure to turn off system restore restart then turn it back on to get rid of it from old restore points.
3. you can download utilities to a disk from another computer and run them on yours to clean it.
Superantispyware, malwarebytes anti-malware, avast, TDSSkiller is a good one that is free. Eset has a free tool that is awesome.
Windows defender should be installed try running that.
But mainly you want to run everything you have on your computer to see if it finds anything.
3. If all that fails then uninstall your network adapter and then restart and it will discover it and re-install it...you might be able to get on the internet for a bit if you are still infected....but I would use another computer to download to a disk and then run from your disk.
4. I would not worry about this as even though it is aggravating, you will be able to fix it..there are many ways...just let me know what is working for you...and we can go from there.