How to zip uncompressed files:
1. go into the folder which you want to compress
2. tar cvf filename.tar *
3. compress filename.tar //you will get filename.tar.Z.
//step3 also can be like this: gzip filename.tar,you
//will get filename.tar.gz
How to Upzip compressed files:
1. copy the filename.tar.gz file somewhere you can create files and directories
2. gunzip filename.tar.gz
3. tar -xvf filename
//well to compress step2 and step3 into one step:
//tar zxvf filename.tar.gz
//If you want to unzip filename.tar.Z,
//step2 should be like this: uncompress filename.tar.Z
this should be enough to solve your yesterday's problem