I have the EXACT same model computer--Compaq 5204. The bad news is that I have never encountered a problem like that. I have used different monitors and operating systems and have had no problems. So all I can offer is a few suggestions:
Does the sound only break with that one particular monitor?
You say the sound works until you add a monitor. Do you mean it works with a different monitor or only when the system is running without a monitor at all?
As mentioned above, if you have added or changed hardware, or messed with the BIOS, be sure to check the settings. The BIOS key for this machine is F10. I hope you didn't low-level format the hard drive, because (supposedly) the BIOS won't work properly if you do that and you will need to "reinitialize" the disk. Or so I've heard. I'm not going to try and find out.
If you think it's worth the effort, go to http://www.knopper.net/knoppix/index-en.html
and get a Knoppix CD. Boot from it, and see if you have the same problem. But it's a lot of work if you have a dialup connection like me--700 MB
! However, that CD is the best troubleshooting/portable os/rescue disk/whatever I have ever seen
. (While I'm on this tangent, I have to ask--is win98 taking 10 minutes to boot up on your system?)
If you're going to poke around inside the case, you'll want to look at the Compaq message (yes that's what it's called), here
. You wouldn't believe how long it took me to find that documentation.
]I intalled WinMX and it found the monitor and sound on its own.
What is WinMX? Google says "filesharing program." So......
]I did not use the recovery disk when I re-formated the computer
Er...then what did you use?
Hope we can get to the bottom of this