Bummer...
You might try going here to read up on <a href="http://www.compaq.com/support/techpubs/customer_advisories/DD990317_CW02_0.html" target="_blank">Starting Setup VP 1.72 by Pressing the F10 Key on a Deskpro 4000</a>. It tells you that the "...Computer Setup and PC Diagnostics are both pre-installed on the Diagnostics Partition. The diskettes in this SoftPaq can be used to update these utilities on the Diagnostics Partition or to restore them if the Diagnostics Partition has been destroyed. Both utilities can be run by pressing F10 during power-up or reboot when prompted in the lower right corner of the screen on some models or when the cursor jumps to the upper right corner of the screen on other models. Or they can be run directly from these diskettes."
Also, go here to download <a href="http://www3.compaq.com/support/reference_library/viewdocument.asp?countrycode=1000&prodid=17|Deskpro+4000&source=166906-001.xml&dt=264" target="_blank">Troubleshooting Guide for the Compaq Deskpro Family</a>.
Good Luck!<br />DonJ