no diagnostic?

hi everyone:cool
i have a client w/c give me a wow problem regarding his pc.
ahm an old one,,a socket 7 type unit.
now m tryin to repair it.cpu is good,memory also,board is beeping
the problem is i have no hardware w/c i can deal wid to try trial and error styles
no display is the problem and power supply is good...

thnks in advance for all d help!:major
i need it badly..
i try to convince my customer to purchase a new one,but he refuse
cause his unit has centimental value to him!!!:zzz