Can't right-click-drag my mouse

As the title says, I can't right-click-drag my mouse, i.e. the icon I'm trying to drag doesn't "stick" to the cursor, and the context menu that pops out on release of the right mouse button is the menu that would appear if I right-clicked on the spot, NOT the right-click-drag menu (Copy Shortcuts Here, Extract Here, etc.).

However, I can do it in Safe Mode. I've tried uninstalling and reinstalling the mouse to no avail. Interestingly, when I open Mouse settings in Control Panel and click the check box to switch the primary and secondary buttons but without clicking Apply yet, I can get it to work.

Anyone have any ideas?

Take it apart, shake all of the crumbs out and clean it
Buy another mouse

Gee, thanks.

Anyway, mark this as solved; after sorting through my startup programs I found that VistaSwitcher was the problem, with it's "Replace Right Mouse Button + Wheel" option. Disabling the setting fixed it.

Thank you for posting back with how you resolved the problem