Hi Brumas. I can help on some, but not all your questions. I have just fitted a new hard drive and was very impressed at how easily installing Windows XP was. The sequence I used was this.
1. Format the drive and install XP.
2. Install SP2.
3. Install motherboard drivers.
4. Install Modem
5. Install Mozilla Firefox (I am now in a position to download any files I need)
6. Install antivirus and firewall (these can now update themselves through the internet connection I have established).
7. Install all other software.