Vista sp 1 (64bit ultimate) - cannot connect to wireless networks

I have a HP Pavilion a1357c (original OS - 32 bit XP MCE) that now runs
Vista Ultimate 64 bit sp1. Ever since I installed sp1 my wireless card does
not work. The wireless card is based on Atheros 5006x chipset. I have
updated the drivers to the latest.

I can see the wireless network in the vicinity if I disable and then
re-enable the wireless device. However, if I try to connect to my network it
never completes making the connection and then it loses sight of the
networks. I have to then disable and re-enable wireless.

Any suggestions on how to get this resolved is much appreciated.

Thanks