If it says to use that key, then it should work, assuming you are looking at your correct model. Some units are set up to use the F keys different ways, you may need to use a function key with the F key or not, or you may not be tapping it soon or early enough. I suppose the "alt F10" means to hold down alt and tap F10.....
To test, can you get into the F8 screen for recovery options? If you are just trying to repair a boot situation, you may not need a complete system recovery.
Do you have a model number to the computer so we can check?