Hi again.
Since the computer recognizes the printer but not the scanner I still think this has to be an issue with the HP software.
Do you have a third party program like Photoshop that you can try and run the scanner from (I never do it any other way so my experience with using the factory software is limited) but I find literally dozens of people who have this problem and no real solutions.
Some do say that they can scan with other software but not the HP apps.
Most say the scanner was working normally and then quit and now they can't find any way to get it to run again.
I have to say that I swore off HP products years ago when practically every one I knew was having similar problems with their HP stand alone scanners and getting no help from the company. I knew a lot of people using HP scanners because I'm a graphic designer, and back then almost everyone used HP products. Not true anymore.
Re-installing Windows may fix the problem, because it seems to revolve around something in the HP software getting corrupted and not being able to fix it, even by reinstalling.
If you wan't to try doing a repair install of Windows 7 to see if it fixes it here are the instructions.
Repair Install - Windows 7 Forums
If you have service pack one installed you have to remove it first.
How to uninstall Windows 7 Service Pack 1 (SP1)
What I would do myself it go and buy a stand alone scanner.
In fact I'm going to!
I decided since I seldom use my scanner (almost everything comes in digital now) to go with a Cannon all in one the last time I needed a new printer.
What I found was that even though I went with a high end model the quality of the scanner was very poor.
Not close to the level of reproduction I was used to in my scanners over the years.
So now I'm going to have to go back to a stand alone scanner.
I'd recommend something like this for an not professional.
Link Removed
Sorry I couldn't be of more help but there doesn't seem to be any good answer for this.
Maybe someone else will have an idea!
Mike