My daughters pc has an asus m3n78 pro ddr2 motherboard i would like to swap it for a Biostar mcp6p3 ddr3. (I have already done it but i reversed the process being vista o.e.m). Everything worked but i could not connect to the internet i just wondered is it because of the o.e.m causing issues i do not want to reinstall the os. I uninstalled all the drivers before swapping and later installed all the new drivers. Both have nvidia chipsets i think the asus as 1Gbit internet and the biostar as 100mbit and i also wonder if the o.e.m is thinking thats different. I was surprised vista booted.
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I am surprised as well that vista booted. Have you checked in BIOS if the network controller is enabled?
The only option i had in BIOS was in south bridge mcp61 configuration: MAC LAN AUTO OR DISABLED i checked that and reset bios.