I have a normal installation of Qlikview server on one of the servers and i want to reisntall the server . Can anyone please help me with this i want to retain the original settings after re installation?
Onno already replied to you in the Personal Edition FAQ area (please don't post the same question twice, we can all see and read the first one in the global overview). In the Qlik database, your license code refers to a registration of CALs, nodes, expiry dates and all other stuff that you bought from them. As long as you keep your license code and the control number, you'll be able to reactivate your QlikView installation.
There is however another way to read your question: "what happens to my CAL assignments. Are they lost as well when I reformat my Windows server?" The answer is Yes. If you forget to make a backup of the files and locations mentioned above, you will have to do the license assignment all over again. And that's nothing to worry about if you only got -say- 10 CALs. But it will get tiresome if we're talking about 100s of CALs.
If you want to keep your CAL assignments (and the user accounts), make sure you backup a file called "CalData.pgo". It usually resides in 2 places: the Document Root folder and C:\ProgramData\QlikTech\QlikViewServer.