Netbook wireless connection

The issue may be with router, not with the computer.

Do a scan using your wireless adapter's or network utilities and if there are neighbouring wifi networks, change the router to a channel 5 stops from the strongest neighbour.

While there check that the router has not been set to automatic channel select -- auto sometimes switches channels unexpectedly and some OS can't keep track.

Also relocate cordless phone base, video sender etc away from computer/router.