CreateProcess() Hogging Resources?

Within the same procedure, I start a timer and later I call
CreateProcess() with the param NORMAL_PRIORITY_CLASS. The
timer stops running immediately, CreateProcess seeming to
hog all the resources (though Task Manager shows between
1 and 5% of CPU Usage). How do I get parallel processes like
this timer to continue working, i.e. are there parameters in
CreateProcess I have to adjust?

Any hints much appreciated.

Andreas