Just bougt a GT31, but it wil not connect whit the navilink program on my computer.

it cant find the usb poort ant have 4 on my computer ant tried them all.

Please help me?

did you install the driver for the device yet?
the unit has an onboard serial to usb-converter installed for which a driver is needed and which is not installed with navilink software automatically. also the driver differs for old gt11/amaryllos units.
ok but how can i install that driver?
The serial-to-usb convertor Thorsten is referring to is a chip made by Prolific, the PL2303. Since you do not seem to have the driver installed, try installing the driver that you can find here:

BTW, in general I never use Navilink to download the data on the GT31. I simply open the lid on the bottom side of the GT31 with my teeth (yes, my teeth) and remove the SD-card. I copy the datafile from that day to my laptop, analyse it and upload the data to Much easier in my opinion. :)
If i open the SD-card i get all SBN files and how get i that on GPS-speeddurfing??