as of around two weeks ago I've been having really weird interactions with the Internet that I can't explain, but please keep reading. I've tried looking for the issue myself and haven't found anything, any help is appreciated.
Things to know -
I'm running Windows 10
My ISP is Telstra and this is a home/family connection.
I'm using a wired connection
My modem is a Netgear Wireless Cable Gateway CG3100D-2
I have two diagnostic .bat files on my computer, one which pings my modem and one which pings Google. I can ping my default gateway, 192.168.0.1, just fine with a <1 ms response but i can not ping Google (or any other site) any more, command prompt responds with "Request timed out.".
Pinging 192.168.0.1 with 32 bytes of data: Reply from 192.168.0.1: bytes=32 time<1ms TTL=64
Weirdly though, if i ping a site with the connection disabled I receive "Ping request could not find host Google.com. Please check the name and try again". In whatever state this is, I receive "Pinging Google.com [126.96.36.199] with 32 bytes of data:", which is Google's IP address and then I receive lines full of "Request timed out.". I find it weird because it still retrieves the IP address but won't interact with it.
Pinging Google.com [188.8.131.52] with 32 bytes of data: Request timed out.
Also something I found, when i go to speedtest.net i get around 30mb/s download and 1 mp/s upload which was normal for me prior to... whatever happened.
Another thing I found is that when I run League of Legends, (don't worry you don't need to know about the game to understand what I'm going to tell you) and I attempt to log in, my user name and password are authenticated meaning it will continue the logging in process if the username and passwords match, using a random user name and password presents me with the 'incorrect user name or password' screen, so i guess that means that I'm communicating with the login server in some way, but I'm stuck in a process after that titled "Logging in..." and then I get a connection error.
Additionally, the logs in my router show a table with description, count, target and source as titles of 4 boxes. There are three different titles under the Description box, TCP- or UDP-based Port Scan, LAN-side UDP Flood and SYN Flood. The targets and sources appear to be my external IP address, my laptops internal IP address, another internal IP address that isn't being used, my DNS servers, 2 other random IP addresses and Google's IP address. At first I thought I had a virus and scanned my computer using Avira antivirus, another program named SpyBots - search and destroy, and also Windows Defender. Windows Defender returned 1 infected file which I promptly removed but the results continued to surface in the logs.
Things I've tried doing to fix this include -
Allowing 'Networking - Echo Request (ICMPv4-In)' in my firewall settings
Disabling my firewall
Disabling my antivirus
Resetting my modem
In the end I don't think it's a DoS attack or a virus and is probably due to bad or expired configuration but I don't know what to do from here, so I'm turning to this forum for help. P.S English isn't my first language and this was hard to type and explain while being understandable, if something doesn't make sense or if i used the wrong word please bear with me. Thanks everyone.