When working with integers, try to avoid such things as a/(b/c). Integer division discards a lot of information. Always try to perform as few divisions as possible and as late in the expression as possible.
Instead of frameCount / ((timeGetTime() - startTime) / 1000)
try frameCount * 1000 / (timeGetTime() - startTime)
Except in the case of integer overflow (which can often be accounted for), multiplication doesn't discard any information.