A. A ZIP file is one that has been compressed -- the size has been reduced so it can be transmitted faster over slower Internet connections, or take up less space on a disk. The file can be unzipped by using a program such as WinZip, PKUNZIP, or other programs to expand the file back to its original size. If everything works correctly, the expanded file is identical to the original file before it was compressed. If you have a group of files that need to be kept together as a bundle, they can be "zipped" together into one file.

The type of compression that unzips to recreate the original is called "lossless compression". Another type of compression that reduces the file size of bitmap pictures by simply eliminating "unnecessary" bits is called "lossy". The latter is the way the jpeg images work and the bits removed are not recreated.

A full-function evaluation copy of WinZip is available on the web, just type in WinZip in the address line. Download WinZip 8.1 SR 1. Double-click on the filename (winzip81.exe) and this self-expanding file will install itself for you. You will now be able to double-click on the ZIP file (filename.zip) and WinZip will open to expand it.

Q. How do you change the background squares beneath the desktop icons in Win XP?

A. Follow the path Start > Control Panel > Appearance and Themes. Under Pick a task, click on Change the desktop background. Near the lower right-hand corner is a Color option. Click on the down arrow and select a color either from the palette showing or click on Other for more color options. Click OK.

An alternative way to get there is to right-click on the open space of the desktop and then click on the Desktop tab. Then proceed as directed above.