no access to some anti-virus sites & system restore stays blank

i have recently had a problem with the weather channel desktop weather tool bar .i had to uninstall so i did & iot wouldn't fully uninstall. then i found a virus from running e2 free edition found a trojan.win32.vudo!IK & quarantined it but now, i still cannot reinstall weather channel desktop. i have tried putting another anti virus on which the screen 4 it would show up blank. also my yahoo messenger will let me send messeges but not recieve my windows media player will not load up. i am seriously thinkin that it is some virus that i cannot get rid of .i have windows xp please someone help!!!!!!!!!!!