This morning when I fired up the computer, the gadgets were blinking at the rate of about 1/10 second off every 2/3 of a second. All control panel windows and the border on the taskbar were in sync. I have the sidebar itself off so that just the gadgets show. I fooled around with it for awhile trying to see if I could figure it out; turned the sidebar on, exited the sidebar, rebooted, exited the sidebar again, restarted the sidebar, finally exited the sidebar again, which stops all the flashing. But I miss my gadgets. Anyone have any ideas how to get them back to normal?

Without more details on any performance/reliability/events I'd have to go straight for a repair install of Vista: http://vistasupport.mvps.org/repair_a_vist...e_vista_dvd.htm

It was my trusty tried-and-true WallpaperChanger. When I shut it off, the gadgets stopped blinking. I have not yet tried to reinstall it, but it may be corrupted some way.

Try checking in Event Viewer for more details on the problem. Go to Start and type in "eventvwr.msc" (without the quotes) and press Enter
Expand the Windows logs category and click on the Application logs. Scroll down to look for error messages around the time that this occurred. Then do the same thing for the System logs.