The problem is not with your computer or with your ISP, but with Steam's new Server Browser configs.
There are several ways to fix this:
1)
Regedit: (Best Result)
Open up your regedit by clicking start: "Regedit" then go to the following location:
HKEY-CURRENT-USER -> Software -> Valve -> Steam
Then create a new string value and name it "CafeRate"
The Value is set to 10 000 By steams default configurations, and can be set as low as 2000.
This will limit how many servers steam will ping per second to update, hence your ping being over 1000ms and being instantly kicked.
Try setting this to somewhere around 3000 or 4000 and work your way up until the issue occours again, and then select the last functional rate.
2)
Steam Settings: (Optional)
Go to your steam settings and select the "In-Game" tab, You will see a dropdown menu titled:
"In-Game server browser: Max pings / minute". Change this value around to a lower setting until your ping starts getting better.
You're welcome, let me know if any of this works ;)
