One of the major issues that many have with Vista is the security measures that were built into the OS. This was also the main complaint that users had of all the Windows platforms, the lack of security. So the conundrum was how much security vs. program accessability. Microsoft did not handle the juggling act of these two counter acting philosiphies. One somewhat problematic issue that I have with Vista is where I can store data files that are associated with programs that are Vista compliant. I can no longer save those files where I want to. I have to defer to Vista and its security measures of where they believe those files should be stored. The other is the myriad levels of "parental protection" that now exists. They can be turned off but in doing so, you remove other levels of security.
This is where many people have their complaints with Vista, I do as well but gageing the whole against the individual parts, I'm ok with what they are attemping to accomplish. I do understand that many are liking Windows 7 as they have addressed many of the Vista problems.
As for the scanner, I may have found a fix for you. HP it seems is not all that accomodating to their customers when it comes to Vista compatable drivers. There is a program called Vuescan that apparently overcomes the imcompatability problem with Vista and HP. Here is the link, http://www.hamrick.com/ .
Although the program cost a couple of bucks, you can download a trial copy and test run it to see if it works. One thing that I read was someone downloaded the trial copy, ran it, it worked. They then uninstalled the trial version, loaded the original HP scanner software, and their scanner started working. My assumption is that the associated scanner driver that came with the trial version did not "uninstall" and remained resident in their computer. Once they reloaded the HP software, HP did not overwrite that particular driver and so when they ran the HP scanner app again, it worked because of the resident Vuescan driver.
Ok, I have yapped enough. Hope this helps if you eventually get back to the scanner.