Yes you can... but maybe (only had a quick look) not
through the settings in jEdit.

Personally I use a free utility called Starter by a
company called CodeStuff, see weblink:
http://codestuff.tripod.com/
If this link doesn't work, Google "codestuff starter"

Starter has three tabs at the top for the three
main functions it offers:
A. 'Startups' - shows all the programs that start
up on your PC (this is the one you want)
B. 'Processes' - shows the processes currently running
C. 'Services' - shows the Services on the PC, witch
are running, stopped etc.

1. Open CodeStuff Starter
2. Open 'Startups'tab
3. Find the entry relating to jEdit
4. Un-tick the check-box next to it
5. Confirm disabling that item from starting up by
clicking 'OK'

That's it.

This would also work for other programs. I personally
stop the
-Java updater
-MS Office quick-launch
-Adobe Reader quick-launch
-Real Player quick-launch
-Winamp quick-launch
on my personal computer.

If you ever want to re-enable a program't automatic
startup, you can simply go and re-tick it's check-box.

Hope this helps.

-Magnon Damant