Some times my network and VPN connection blocks (magic button is only solution)on WinXp sp2,it had doing that under sp1 but had a conflict with program for wireless choosing access point showing some other network and his gateway.It happens mostly over the night when is download something.
Don't know what tipe of router provider had,but the driver for wireless card is TP link TL_WN510G_550G_551G,outside antenna,equipment is under revers so the buying new card isn't a option