If you're using Windows, just do this:
1- PRESS WINDOWS + R key.
2- Write: %APPDATA%
3- PRESS ENTER
4- CUT the file
wallet.dat and paste in other location like
C:\5- Compress the FOLDER BITCOIN located on %APPDATA%
6- Copy to other location like C:\ the compressed file
7- Delete the BITCOIN folder
8- Reinstall the BITCOIN-QT, but DON'T OPEN when finish instalation (uncheck OPEN BITCOIN)
9- Decompress your file compressed on step 6
10- Copy the folder BITCOIN to %APPDATA%
11- Open your software bitcoin-qt and create a new adress.
Hope this help you, sorry for english too bad, I'm Braziliam!