I can't seem to find a function that executes another program without running my processer at 100%. I'm running Windows. I tried all the FAQ's entries. system() is really slow, plus it runs my processor at 100%; spawn* runs at 100% too; so does exec*; CreateProcess runs my DOS program in a new window (I want it to run in the same window); and ShellExecute runs at 100%.

What would everyone suggest using?