Port/Com driver problem! Please Help!

I am hoping that someone here can help me.

I bought a Fortuna U2 GPS receiver for my laptop and I am having a few problems.

It is a PS2 but I have bought the cable to convert it to plug into the USB. Now the problem is its obviously not plug and play and when I try to install the driver it is saying 'to uninstall driver click continue, or cancel'.

I have never installed any GPS or fortuna on my computer before and after reading around on the internet ALOT I have realised there are a couple people that are getting the same problems (recently) but I could not find any resolutions.

I thought then if maybe I assign the driver to the com port that the usb receiver is going into then it might work.

I now go to my Device Manager and here is not Ports/Coms section to change or update drivers! It has just gone.

I am confused as to how to get this driver to the usb port so that my software (autoroute 2006) can detect it.

Thank you so much for any help !
Jennifer