Cannot find wireless network, and 2nd core is busy

I bought a new dell inspiron 1501, with an amd turion 64 x2 tl56, running
vista home premium. Sometimes when surfing the internet with ie7, it will
drop the wireless connection, and be unable to find any wifi networks. I
know this is not my router, as my neighbour's laptop sees it ok, and I can
usually see 2 other networks. At the same time, core 2 starts running at
100%. Task Manager can't see anything using more than 3%, the total coming
to about 20%. What's going on?