Thanks...is there an equivalent C# implementation? My EXE is a C# program. Loren

Thanks Brad...I'll do some more investigating. Currently I am using CoRegisterClassObject(ref myGuid, myApp, ComAPI.CLSCTX_LOCAL_SERVER, ComAPI.REGCLS_MULTIPLEUSE, out myReg) which should have worked but is creating a new instance which generates a new windows form. Loren