May you want to re-install your windows and want to keep all your previous Skype chat history, to do so you need to backup your history.
The procedure for backing up your history files on a Windows XP machine is the following:
Locate the folder “Application Data\Skype\<your username>” and copy it to another location such as a CD or DVD-ROM.
In Windows Vista it will be "AppData\Roaming\Skype<your username>”
To restore the history files just copy the files back to that folder.
These files are stored as .dbb files and can only be read with Skype itself. Unfortunately you cannot recover from a corrupt history file.
Be aware that the above files contain all of your chat room history files. You cannot save separate chat room history using that method.
