networking blues

this should be an easy one for you have more know power
than me!

Just wondering if it matters if all 4 computers on my
business network use the exact same networking adapters
or not. I know the main problems that I am having are due
to mapping requirements for the quickbooks premire 2005
program that we use. two computers that I have recently
updated from 98 to xp home edition have the netgear
adapter installed and the two power spec (on the fence
about these two gems) have factory installed realtek
RTL8139/810X family pci fast ethernet NIC(?) in them.
sharing 2 different printers among the network is the
main problem. I own buchanan Hardwood Flooring Inc. in
cincinnati ohio, if anyone would help I will return the
favor with free product or service. Owner, IT guy,
service teck, networker, lots of hats!!!!

thanks guys