Open running processes

[DeRRudi]

Hi all,

I have a programm. In this program i've made the restriction that only
one instance can run at the time. (done with mutex).
Now i'd like it to open the running (make visible) instance when
someone want's to open it a second time. 
Does anybody know how to do this? I hope you all understand what i
mean. My English isn't to good...

Greetz Rudi