1. Vista would struggle.
2. Prefer without any extra Partitions.
3. Should be safe, but if you change to Vista, some might not work.
4. Re-install over it.
5. I never partition, IMHO partitioning sometimes causes more problems.
6. Better answered in Network Forum.
7. In XP Start>All Programs>Accessories>Command Prompt.
8. Don't think so, but others might have other suggestions.