Complex sentence: This was in part due to the fact that sound cards did not originally follow any commonly agreed-upon standard and were largely incompatible with each other, whereas the PC speaker was the only sound system that could be regarded as universally present.
Split into simpler sentences: This was in part due to the fact that sound cards did not originally follow any commonly agreed-upon standard, and were largely incompatible with each other. The PC speaker was the only sound system that could be regarded as universally present.