Hi everyone.

I'm trying to build a Windows 9x-era PC with the parts I can find. Please keep in mind that I live in Japan, so availability of retro parts is scarce, meaning I have to make to with what I have now (no recommendations for purchases, please).
I managed to find an i815E-based motherboard, AOPEN MX3S with a 1000Mhz Pentium III chip (attached). Unfortunately, this card has no ISA slots.

I believe that the integrated audio worked once and then suddenly stopped working (the integrated LAN port is recognized when appropriate drivers are installed, but the ethernet link stays down - could that be related? I installed an RTL8169SC which I can't find the Windows 95 drivers for). I thought that the connectors or traces were busted so I went and bought a Creative SB 128 PCI (CT4700 - attached) mainly because it was the only card I could find in my area. The card works great in Windows 98SE and DOS with the appropriate drivers.
However, in Windows 95, when appropriate drivers are installed, the sounds work fine until the first reboot. After then, every sound (including the startup sounds) are looped endlessly for the first second.

I am at a loss: I tried every driver I could find, including SB PCI 64 and Ensoniq ones, but the issue persists. Is this a common issue or something that can be easily fixed? Can DOS drivers be used in Windows 95?
Sorry if the info about the LAN card is unrelated to the issue at hand, and thank you.