long delay in finding wireless network

I have hunted through the forums and cannot see this problem anywhere.

I have a small home wireless network with a desktop and two laptops, the two laptops connect wirelessly.

One of the laptops has started to have a problem recently in that it cannot find my network. The other machine locates it instantly and connects, but this one can take upwards of 15 minutes to find it.

It does see other networks, just not mine. I just sit and wait and it will connect - repair the connection does not do anything, except I suspect it actually delays the connection. once connected the signal strength indicator is very good, and speeds etc are fast. Again once connected it can be a bit interrmittent to start with, but it will very quickly give a reliable connection I can use for hours to watch streaming video etc no problem.

I have borrowed a USB wireless adaptor for this machine and it works instantly - so the the problem must be to do with the internal wireless adaptor in some way.

The offending machine is a Fujitsu Siemens one, and it only uses the windows networking with its own (up to date) driver. The router is a netgear one that is fine and again up to date firmware is loaded (as proven by other units connecting).

Any clues would really be appreciated

Grahampen