When attempting to uninstall Netbeans 7.1 on Windows 7, you may notice that a red border shows up around the uninstall application, and that the files aren’t actually removed from your system.
This is caused by Avast antivirus auto-sandboxing the uninstall application. All you need to do is go through the setting in Avast and turn off auto-sandboxing.
After that is done, you should be able to run the uninstaller without the red border, and uninstallation should proceed successfully.