The Zip file format is one of the most widely used data compression and archival formats. A Zip file usually contains one or more files which are compressed to reduce the file size. ZIP files normally use the file extensions ".zip" or ".ZIP". When you use WinZip to extract a compressed file which has a .zip file extension on a Windows Vista based computer, you will receive the following error message:
This file was compressed using an unknown compression method. The compression method used for this file is 98. error: no files were found - nothing to do
These problems can occur due to the following reasons:
If you are trying to extract a compressed file that has been created using WinZip 10.
The system on which you are trying to extract the file has an earlier version of WinZip.
WinZip 10 utilizes a different compression method which is not compatible with some versions of Windows and also with earlier versions of WinZip.
To overcome these problems, you need to select the Maximum (portable) compression method in WinZip 10. You need to follow these steps:
 

1. Go and Click on File and then Click New Archive.
2. In the File name box or field, please type the name that you want to use for the compressed file and after that press OK.
3. After this go to Add dialog box or field and select the files which you want to add to the archive.
4. Go to the Compression box and select Maximum (portable) and then click Add.

You will be able to overcome these problems by following the above mentioned procedure. Sometimes after a Zip file has been downloaded it fails to open. You will need to use Zip repair software in this case.
Stellar Phoenix Zip Recovery Software helps you to recover and repair corrupted Zip files. This software scans the selected Zip files and uses an advanced algorithm to restore damaged Zip files to their original location. It also supports repair and recovery for corrupted Zip archives. Additionally, the software helps save Zip files to any user specified media. Stellar Phoenix Zip Recovery Software will help you in overcoming all Zip file related problems.