I used nLite to slipstream SP3 onto a disc I had previously made with nlite that had SP2 on it. When I boot from the disc and begin the install process, I get the message 'Setup cannot copy the file xxx' immediately. If I skip it over, a few files will copy then I will get the message again and so on. If I make a new disc integrating drivers and other tweaks, but not SP3, then it works fine.