HTC Desire :: Change Song By Sliding Finger - Unable To Use Wifi

I am new here and i have just got my HTC desire. Its a great phone. When i clicked on the MUSIC button i noticed a few pre-loaded songs and i could move from one song to another by slidding my finger across the screen. When i downloaded my own songs(and deleted the pre-loaded ones) the phone just wouldn't move from one song to another by slidding my finger across the screen. And about the wifi. I use the POWER CONTROL widget. When i pressed the button for wifi, it started connecting and the green line under the button appeared and a few moments later(2 sec) also that sign on top of the screen. But i wanted to remove my google account so i had to use the option FACTORY DATA RESET. Now when i click that wifi button it starts connecting and that green line under the button appears, however now it takes 5 seconds or more for that sign on top of the screen to appear(before that sign appears i can't use my wifi connection).