I have to reinstall windows on a compaq, but I can't boot to the recovery partition - pressing F10 at the bootup screen like it tells you to doesn't work (windows just boots as normal) & there isn't an option in the windows bootloader for compaq recovery.

What do I have to do to use the compaq recovery?
If I can't use the compaq recovery partition, how do I force windows to call the partition I'm installing it on C drive instead of D drive?