HP, bless them, makes some fine printers. They also make very helpful software, but it is, in my opinion, bloatware. Services, tray apps, drivers, and a slew of "helper" applications. The software developer in me loves that they employ so many devs, but the Windows user in me cries when one of those fine apps has issues.
So, my "HP Photosmart C4385 All-in-one" is a wondrous device, as it works generally very well over Wifi. However, my Vista computer occasionally decides it can't find the printer, or that the printer is perpetually "offline", requiring a reboot. I discovered that instead of rebooting, I could restart two particular Services ("HP Network Devices Support" and "HP Cue Device Discovery Service", in that order) and it was happy again. In fact, jobs stalled in my Print Queue would then immediately print. Woohoo!
After doing this for the 348923849th time this morning, I said "to heck with this, I'm writing an app to do it for me". So here, as quick and dirty as a little league shortstop, is a Windows console app that will reset those services. I can't guarantee with which HP models this will help, or if anyone else is having this exact problem, but if so, enjoy.
You just run it WITH ADMIN PRIVILEGES (notice "Privileges" contains the word "vile", and also "leg"...). It produces a console window that will appear and disappear quickly. When it's done, your printer will either then start printing, or it won't...
802.11 / Wifi -- one of the greatest, and most annoying, advancements in personal computing.
HPReset -- executable only (RUN WITH ADMIN PRIVILEGES!)
HPReset -- source code (RUN AWAY)