1. Wire the laptop to the router.
2. For each game research server disconnect questions and answers.
3. What's not stock on the machine? Anyone add Mcafee, Norton or other "protection suites?" Why I ask is for gaming these can often step in and block. Avg/avast offers a game mode due to this issue.
4. Laptop gaming can cause the machine to heat up and see WiFi and other problems. Get wired as in step one and place the laptop on a cooling pad.