I'm sorry you are frustrated. I can tell you that, in my experience, not being able to establish parallel communication is the exception, not the rule. I personally use XP Pro and, as a distributor for Pico's automotive line, I have customers on five continents. Only three times have we had to go USB because of a communication issue.
I have no idea why certain PCs just can't communicate with Pico over the parallel port, but it has to do with certain individual PCs, not the operating system. If it was an OS issue, it would be common to all computers using a certain OS and it is not. The problem is machine specific.
I am not a software engineer, I am a Master Journeyman auto tech and trainer. I sure don't envy the job the Pico team has with all the different PCs and operating system issues. I do know that some PC manufacturers tweak the OS shipped with their units to conform to their configurations. This creates unique behavior qualities that another user of the same OS will not experience. I suspect the issue may be related to this.
I do understand your frustration. Don't give up man. The PicoScope is awesome. You can't get anything better. If it is just the USB adapter standing in your way, get it. You can't come close to the power of PicoScope at twice the price anyway, so the cost of the USB is really not relevant. You'll still be way ahead on power and price.
THE PicoScope Automotive Authority
In North America