You tell you get numbers, so it's possible to connect. But when they go, the communication is lacking. The laptop has no other things running? XP isn't a problem, but a bad running XP can be. If you look in taskmanager processor is not busy with high load?
Often wenn laptops aren't used a long time, they start to try to update all things, keeping it very busy.
As I understand, this old laptop is what you used before for Guzzidiag?