Is it possible to prevent Mesh from automatically starting?

Yes, there is a way to prevent MESH from starting automatically in case you are not willing to uninstall the software. The method is to disable the service from Windows start up and you can follow the steps below if you want to do so:

SOLUTION I:

   1. Click on "Start"
   2. Click on "run" and type "msconfig" (only msconfig) and press enter.  Windows Vista and Windows 7 users can directly type "msconfig" (only msconfig) in search bar after they click on start.
   3. A "system configuration utility" window should pop up on your screen.
   4. Click on the tab that says "Startup"
   5. Uncheck all files that mention "live mesh" or "Mesh"
   6. Click on "Apply" and "OK"
   7. Restart your system.

NOTE (for step 5):
-->In case you are not able to find any file by the name ""live mesh" or "Mesh" ,
 please check mark the box that says DISABLE ALLand then follow the steps further.
--> "Disable all" will remove all the items starting up with your Windows OS and will speed up your computer as well (No Software will be uninstalled).

SOLUTION II:

The second solution to the problem would be to change the service start type to Manual from within the Windows Services.
   1. Click on "Start"
   2. Click on "Control Panel"
   3. Click on "Administrator Tools"
   4. Click on "Services"
   5. A services window should pop up on the screen.
   6. Set the Start up type of the "Live Mesh Remote Desktop" from "Automatic" or "Delayed Start" to "manual".

NOTE:  You can bypass Steps 2, 3 & 4 as following:

Windows Vista and Windows 7 users:
    1. Click on "Start"
    2. Type "Services.msc" in search bar and press enter. Follow steps 5 and 6 after this.

Windows XP users:
    1. Click on "Start"
    2. Click on "run" and type "Services.msc"(only Services.msc) and press enter. Follow steps 5 and 6 after this