installed new video card now driver problems

Motherboard

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Manufacturer: Asus
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Motherboard Name: A8M2N-LA
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HP/Compaq motherboard name: NodusM3-GL8E

HP pavilion a1677c

Now the first thing that happened is my old video card went bad. I installed a new radeon HD 4870, i put in the disc it came with and thought everything was all good. Until i try logging on my ventrilo server and noticed that i no longer had a sound device. I wasnt sure what happened and i thought that re installing windows would fix it. It didnt, and now i have more problems. Not only the sound going out but re installing windows messed up my network card or something because i can no longer connect using my ethernet port. Originally the pc came with Microsoft Windows XP Media Center Edition 2005, the windows i installed on it was the xp 64 bit edition. In the device manager there are two yellow exclamation marks. One saying "other PCI bridge device " and "sm bus controller". Im not sure what these are but im sure that they are a problem. I seen that the original audio was using a realtek ALC 888 chipset. I am downloading that driver right now and hopefully i can get my sound back. Any helpful feedback is welcome. Thank you for your time.

 

Well that link you provided helped extremely now i have my networking back. Although when i tried to install my realtek hd audio driver, it said i needed to update my HD audio bus driver and to go to this site support.microsoft.com/?kdib=901105
I tried going there but it just makes me use search engines and im not sure which one to go to. Maybe you can provide me with another successful link?