Hm, tested on Vista (x86) again, but still no joy with the context menu. Even the regsvr32 jqcm32.dll doesn;'t work: 'Can't load module JQcm32.dll' (but then in Dutch: "Kan module 'JQcm32.dll" niet laden.").
One peculiarity maybe: The Win7 x64 systems I tested JottiQ on, both have VS2010 installed, and on both WinXP and Vista I didn't have even .NET 4.0 installed until it wouldn't load JottiQ so I had to install that using Windows Update. I installed the plain 4.0 Client Profile thing, but it might still be missing the VC++ runtime (as you mentioned in a PM).
Also trying to enable this feature from the settings menu doesn't give a shielded OK button and doesn't enable the context menu entry, but seeing that regsvr32 fails explains that I guess.

On the 'single instance' issues, Inno Setup does natively support checking for a Mutex, and with a small add-on dll, can also check for a process name or windows title. Maybe that's enough?

I'll dig up the code to add .NET 4.0 and VC++ runtime to the installer today and post or link it here.

Just tested JottiQ 0.9.5 on Vista 32 bit.
Guess Vista doesn't like the shell extension, because it's not showing in the context menu of Explorer, or at least not for the files I tried it with. I'll do an uninstall/reinstall to see if I accidentally unchecked that option. [...] And that didn't help a bit, neither when checking the 'Explorer Integration affects All Users' option, so that might need a fix. Vista's UAC is turned off, btw.
This worked fine on 2 of my Win7 x64 setups, one with UAC in it's default setting and one with UAC turned off.

That's a HUGE improvement and very clever; the ones that kill me are the ones that have to "dock" to recharge, and so can't be used at all while recharging.

-mouser (December 27, 2010, 11:04 AM)

That was one of the reasons for me to add a wired mouse placed on the 'other' side of my keyboard, and training myself into using it with the hand/arm on that side as well. It took a few weeks, but I now can use a computer even if my 'good' arm would be disabled/unavailable for a while.
Another reason was the avoidance of RSI by switching arm-usage.