Well, a few possible options. First, take a look in your machine - do you have an open PCI slot for another soundcard? I've seen some boards in these machines that have 1 PCI slot, and 1 AGP - talk about expandable.
Provided you have an open PCI slot. You may be able to disable the soundcard built into your motherboard by entering the BIOS. To do this, when the machine is first turned on, and doing the memory count, hit Delete.
This doesn't usually apply to Compaq's though. Try F1 or CTRL/ALT/Escape, or holding down the escape key while turning on the power. If none of those work, call Compaq tech support with your machine model number and they will tell you the secret. Someone on the BBS may now if you provide the model #, I work on Clones - Brand Name machines very rarily.
In the BIOS it you may see an option to enable or disable the onboard sound.
If this option is not in there:
With Windows all booted up, go to device manager(right click my computer, select properties - then select the device manager tab along the top). Under Sound/Video/Game controllers, double click that - you should see your sound card listed in there - might be opti or ESS or crystal or something like that. Double click on that, you should see a check box that says "disable in this hardware profile". Checkmark that for anything related to sound in there. Click OK and then OK again, will ask you to reboot. Let it reboot.
Shut down, than install your new sound card, see if it works.
Good luck.
