Step7 v5.5, pc adapter error

Hi Guys;

I wanna  make some exercises in step7 v5.5. My computer is windows8 I have installed virtual machine as xp sp3. When I finish my ınstalliation I have made set pg/pc interface commmunacition as usb I  could have done some exercise. But after one day later when I tried to make exercises again it given fault.it writes

"your pg/pc has no suitable local connection for operating the device pc adapter"  I checked pg pc interface , couldnt see any properties.The thing wrote local connection "usb" one day ago, but now ıt writes "none".I tried many things and checked on ınternet but couldn't get any solution. Finally I have formatted xp again and install but same fault occours again.I started plc v5.5 new, so could you help me about this asap? What I suppose to do?

Thanks ....

----------------------------------------------------------------------------------------------------
Split from "Your PG/PC has no local connection for operating the device 'PC adapter'".

Closed cause question posted twice.

The second thread with the subject Step7 v5.5, ''your pg/pc has no suitable local connection for operating the device pc adapter'' is published within the conference STEP 7 Additional Software.

Best regards
Min_Moderator