Hi,
Note
You're gonna need to be quick for this to work as most fake malware apps tend to disable certain security protocols (Antivirus, Firewall, Internet Access, Task Manager are a few of them)
Step 1 (Accessing Task Manager)
You will need to re-boot the machine and as soon as you see the taskbar (even if your desktop isn't fully loaded), right-click it and select Task Manager.
Step 2 (Killing unknown processes)
Once you succeed in opening Task Manager look down the pist of 'Processes' for suspicious entries. These will look like either random letters/numbers .exe or av8.exe.
Step 3 (Regaining Internet Access)
Once you finish step 2 you need to open Control Panel -> Network and Internet -> Internet Options. Under the 'Connection' tab you need to click 'Lan Settings' and make sure the settings match the image below.
Now that you should have internet access back you can proceed to download MalwareBytes. And fun a full system scan.
Tip
This process can be used to eliminate most fake AV/AM apps