Stopping Sync Center

I am new to using a Windows Mobile device and Sync Center. I have
successfully synced what I needed, but there are times when all I want to do
is work with the device in Windows Explorer. However, every time I connect
the device Sync Center completes a sync faster than I can turn off the Sync.
I have tried to click Stop All before I connect t to no avail. If I end the
partnership, all the synced files on my Smart Phone are deleted when I
connect to my computer. I just need to be able to disable the sync process
except when I really want to sync the files. I am hoping that I have just
missed the way to stop this automatic Syncing every time I connect the Phone
to the computer.