There is no jumper configuration or keypress that the system is going to respond to because it has not gotten far enough along in its initialization to do so. More specifically, your system's BIOS is not completing POST (Power-On Self-Test).
The last Post code being EB is an indication that the last thing that the BIOS did was attempt to invoke the graphics initialization program...
If the system does not have an add-in graphics card, this is an indication that the processor's built-in graphics engine could not complete its initialization. There are a plethora of things that could cause this to happen. It could be corruption in the graphics POST firmware (did you recently install a BIOS upgrade?). It could be a failure in the systems memory (did you replace or augment the memory recently?). It could be a failure in the processor itself (this can happen when systems get to be this age).
If the system has an add-in graphics card, this is an indication of an inability to complete this card's own built-in self-test and initialization. This also can be caused by a great many things. This could be some form of hardware failure in this card. This could be corruption in the card's own POST firmware. It could also be the result of the BIOS being unable to invoke this card's Video BIOS at all. Did you recently install a new or replacement graphics card? In this case, it could be an incompatibility of the BIOS with this card. In Systems this old, incompatibilities can occur with more-modern graphics cards.
I've asked a bunch of questions. Please answer these and we'll see if we can get you further along.
...S
