Now i am trying your thing with nforce drivers. So i renamed all Si13... to nvata, because the .sys was named nvata.sys. I hope it works, be back in a moment...
Nope...it wont work

. I am desperate. Trying to install SATA2 on nforce 4 from 2 days and no result. I guess i will take the floppy at the end.
Updated: I tried the floppy strategy, no success

. Now i am updating all the drivers (for just in case) and the BIOS to 1013 (latest for ASUS A8N-E). Someone told me i should update the firmware of the SATA2 HDD, which is Seagate 160GB. But anyway let me try...