Edit your browser settings to stop using WebMeter as a proxy according to the guidelines available here.
Stop WebMeter running by:
Visiting the WebMeter icon in the system tray area of your computer.
Right-click on the mouse to display the WebMeter popup menu.
Click on Exit.
Optional step. Validate that you have successfully re-configured your browser proxy settings by opening your browser and navigating to a well known website. If this does not work and your network is operating correctly, you may need to revisit step 1.
Remove all WebMeter installation files from where you specified they should be installed. On Windows this is normally "C:\Program Files\WebMeter".
If you are running Windows XP delete the entry at Start > Programs > Startup > Autostart WebMeter.
If you are running Windows Vista or 7 go to the Control Panel and navigate to the Scheduled Tasks administation panel, then delete the entry for WebMeter.