Recently I wanted to upgrade from NetBeans 6.5 to 6.7.1 in Fedora 11. I didn't know how exactly to go about it. So tried NetBeans > Help > Check for updates. It gave option to migrate from 1.5.1 to 1.5.2. Went in vain. Next, I tried checking the Add/Remove software to find some clue of uninstalling NetBeans. It didn't show up any of the Installed S/W.
Hence made up my mind to search manually for any uninstalling mechanism. I found this one working in Linux.
Goto Root > USR > Local > netbeans-6.5
Open your terminal and type sh
Now drag the Uninstall.sh to the terminal.
The address would have got pasted.
Click Yes and follow the Uninstallation Wizard's instructions.
Hope this helps. Comment if any query.