Right, if I'm getting you right, BadToad, your glasses are turning on for a fraction of a second every so often with the possible exception of a few made-for-3D demos. If so, you just need to activate them manually using the E3D or the H3D (e3D is technically for E-dimensional, but any of them work with any glasses, pretty much) activator. Just load it up, right click on the icon in the taskbar, and choose "Stereo on: Resynch".
That'll turn the glasses on - though you'll need to turn on stereo in games separately. Typically the combination for that is CTRL-T, but hey.
Also, if you aren't getting stereo at all, try downgrading your drivers - I know there are some troubles with many newer nVidia drivers, especially with 5200 cards, in working with the stereo ones. I.e. stereo refuses to activate. Which is an arse. But hey - there we go.
This is all completely separate, btw, from the 3DPlus2 software. That will be able to turn glasses on and off itself independent of even whether a driver is installed