Drop of RT73 USB adapter for few seconds

Hello, who can help me with the following problem:
I have a RT73 USB adapter connected to my laptop running XP.
Problem:
The adapter drops after a few seonds than it comes up for e few second and
drops again this going on.
When I use DHCP the IP adress is random when the adaper comes up but never
the right adress. I did a reset of the wireless router without results.
Then I have defined en fixed IP adres within the adresrange of the router
with again no results.
I have installed the latest driver V1.3.0. with even no results. On the same
router another laptop (with built in adapter) is running fine.
It looks to me like a hardwareproblem of the dongle.
Thanks so far. regard Jan