Here are a few install methods if your not sure how to install a theme.
1. Using winzip or a similar unzipping program right click on the zip 
file and choose extract to folder C:\Program Files\Plus!\Themes
Your file should now be,available from your theme program 
in the control panel
2. Or using winzip or similar unzipping program
right click on the zip file and choose extract to:
C:\Windows\Desktop\themename. 
Open the folder and right click on the theme icon and select install.
3. Or, if using a theme manager like Desktop Architect or Dektop Themes,
after unzipping open your theme program, click on install, Browse,
find your theme folder, open it and click on the theme icon then Ok. Select
Your theme from the dropdown menue and apply.
The Bitmap wallpaper in the Tartan Themes should cover the screen. 
If it does not go to start, settings, control panel, display, 
background and chose tile or stretch from the dropdown menu.
If any wallpaper does not cover the screen do the same thing and
Choose stretch. All newer themes are optimized for 800x600 or 1024x768, high color.
Screensavers containing music files may be muted from 
screensaver settings in the control panel.
XP users you must have a theme manager to use themes. 
I suggest Desktop Themes by Left side Software.
If you don't have a theme folder at C:\windows\plus\themes create one.
Windows XP screensavers go in windows system32 folder. 
Enjoy!
Cece@cecemckenzie.com
www.tartanthemes.com