Hi Zhimei,
It's not clear to me whether you want to install the matlab completly or want to uninstall partilcular toolbox , so I am going to provide solutions for both scenarios:
Trying to uninstall the MATLAB completly
NOTE: If you have saved any personal files within your MATLAB directory, be sure to place those files elsewhere before uninstalling MATLAB.
1. Stop the network license manager as described below. If you are uninstalling a standalone installation, skip to step #2.
a. Open lmtools.exe, which is located in $MATLAB\etc\win{32|64} ($MATLAB\flexlm for releases prior to 2010b).
b. Click on the 'Start/Stop/Reread' tab.
c. Click the 'Stop Server' Button
2. Run uninstall.exe from the $MATLAB\uninstall directory to uninstall MATLAB.
3. The uninstaller may leave files behind. To make sure everything has been deleted, go to the directory where MATLAB and the network license manager were installed and delete the entire folder.
4. If MATLAB cannot be uninstalled using the uninstaller or by removing MATLAB with the Windows Add/Remove Programs tool, you can simply delete the MATLAB directory and all of its contents.
Unintalling a Particular toolbox :