my AMD compaq laptop frooze about 4 minutes of operation

i brought my laptop one year ago.

it's Compraq Presario 2135CA, with mobile AMD athlon xp 1800+, DDR 256MB
RAM, 30GB HD and running windows xp pro w/ sp1

i brought my d-link airplus xtreme g DWL-G560 almost 6 months ago.

it was going just fine, my laptop running smoothly, no crashing or anything
when i'm using the laptop with battery and with wifi at home.

then suddenly, the laptop start to freeze when i boot up my laptop with the
wireless card and power by the battery but the freeze doesn't happen when i
boot up my laptop with the wireless card using AC Adapter

so does anyone know what's going on?