You can download the F10 setup from this site... http://h18007.www1.hp.com/support/files/prolinea/us/locate/3_16.html . You can enter it from a floppy, which is what I do on a Compaq of similar age. You can also download and create a disk that will write it to the hard drive, but the hard drive has to be totally clean...not even a partition present in order to do that. It will then install a non-DOS partition that contains the F10 setup.
Compaq's of this type actually put a good part of the BIOS in the 'Diagnostic Partition'. These machines are a major nightmare to work on. You need a set of several diskettes to re-create this partition if it does not exist, and even then your chances of success are not all that good. The diskettes are normally created with the F10 setup BEFORE you exchange hard drives or delete the partitions. You can create them using Compaq's downloadable utilities, the trick is to get the correct ones for your exact model. Good luck on this. The last Compaq I tried it on would simply not let me create the Diagnostic Partition, even though I had the correct setup diskettes and softpaqs.