typeadam

I've searched through some of the posts here regarding wallpaper positioning - specifically tiling - but none of them seem to address my issue.

I have 2 VistaHP machines and 2 XPPro machines.

I have a .jpg, which is 363x261 and want to tile it.
On the XP machines, I just select "tile" from the drop-down menu and TADA! - the wallpaper is tiled.
The Vista machines, however, like to put up a fight. BOTH Vista machines do NOTHING when I click ANY of the 3 options - 'tile' 'fit to screen' 'center'.
The wallpaper (no matter how small) gets stretched to fit the entire screen.

Here's the funny thing: I have 2 Vista machines @ home, 1 @ school, and 1 @ work and NONE of them will tile or center! All the Vista machines I work with only did tiling when the Vista install was fresh. But after a few months of use, it stops.

I'm not the only one to encounter this. I've spoken w/ friends and co-workers and they all encounter this.

Please help - I want to tile a picture! Reinstalling Windows is NOT an option. There's gotta be something in the registry that is preventing the 'tile' and 'center' options from working.

Thanks!
AP