Strange problemm!

The problem is , When i use internet in my dell vostro laptop using wifi router , the internet problem occurs such as PING breaks , some webpages partially open like some images doesnt display , slow speed etc.. and when i use LAN in this laptop it works fine. This problem occur only in my dell laptop.. in my other HP compaq laptop , internet works fine on both WIFI and LAN.. i used both TENDA and TP LINK routers. Same problem occur.. HELP !

try changing your browser....