Is it possible to lock a guide once it is positioned? i would like to be able to NOT accidentally select and move a guide when moving something aligned to the guide.

Not that I know of although I think that might be a nice feature to have.

The best thing to do, would be grab whatever that's aligned to the guide, somewhere besides the part that's aligned. Like if it was a square, grab the square on any of the other 3 sides. If that's not possible, if for example it's a line that's aligned to the guide, you could try moving it from the Selection tool control bar. Or you could also use keyboard shortcuts to move it. (Sorry I don't have Inkscape loaded onto this new laptop yet, so I can't look up the keyboard shortcuts, and I don't normally use them.) I'm pretty sure the arrow keys will move a selected object. And I'm even more sure someone else will reply with the proper keys, lol.

If you want to propose the new feature, please see this topic:
viewtopic.php?f=5&t=484
(I know the title says bugs, but new feature requests, ie - wish list items, are "bugs". In any case, reported in the same place.) Oh, oops druban, I didn't notice the screen name before I typed. I'm sure you already know the keyboard shortcuts and Launchpad.