Please acquaint yourself with the Search this Forum
button/link found at the top-right of this forum. Type in rtl8139 or rtl8139d or 8139d to see all those other threads identical to yours that have already been answered.
And while you're doing so, bookmark or add to your favorites, our Advanced Driver Search Wizard
that allows you to find drivers posted in our driver database. There's also a Simple Search box
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You will then be able to help yourself (the reason why we created this website as it is).