Why is my PC so slow??

My PC, which connects wirelessly, is in the same room as my Xbox. My xbox can connect just fine and run games just fine. However, my PC is so freaking slow. I have put up a WiFi repeater about halfway between the router and my PC, and the PC can connect to the repeater but has no internet access. It says... show more My PC, which connects wirelessly, is in the same room as my Xbox. My xbox can connect just fine and run games just fine. However, my PC is so freaking slow. I have put up a WiFi repeater about halfway between the router and my PC, and the PC can connect to the repeater but has no internet access. It says “connected” but can’t connect to anything. So I switched the WiFi to the main router and the connection is INCREDIBLY slow. It’s ridiculous. I don’t know why my PC has so much trouble yet my xbox works just fine. And I can’t move my router because it is via dsl. What should I do to fix this issue?!
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