My HP Scanjet 4200c stopped working under Windows when I got my new laptop that runs under Windows Vista.  HP and Microsoft support were of no help on getting the issues resolved.  Basically I was told to junk the scanner and buy a newer one.  Since I was pissed off at HP for not supporting this, I opted to buy a new Epson 4990 scanner and am happy with it (end of story).

Well, in June of 2009 I decided to give it another shot on trying to figure out what the problem really was and to my surprise after my Microsoft update of Vista servicepack 2 - the HP Scanjet 4200c started to be recognized again by the Windows Vista operating system.

It's been over 2 years now that I've gotten my old HP Scanjet 4200c working again but it was not without re-occurring failures.

Basically as Vista matured it's security, it made the scanner fail again.

Today's trick is to re-install the driver as Administrator and maybe keep the properties of the exe program files at a compatibility level of XP Servicepack2.

I have NOT tested this under Windows7/8 yet.

My disclaimer:  I am not a Windows programmer or coder so my efforts are from updates and re-installing.  I certainly make no claim that I'm smarter than HP or Microsoft support.  The difference is I took the time to try it out again and again each time it failed.