On networking: just enable NAT in the guest network settings (not NAT network).
As to boot options, I believe you would Start|Run|msconfig and change the boot.ini tab contents to
Code: Select all
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect
On installing the Guest Additions, see user manual chapter 4.