Spreadsheet Won't Calculate
 

I have a spreadsheet that is set to manual calculate because it is a large
financial spreadsheet that I only want to calculate at certain times because
it takes a while. The problem is that sometimes it won't calculate when I
push F9 either. I have also tried control+alt+F9 and it won't calculate
either. What can I do to make it calculate without turning it to automatic??
Thanks!