Hi, guy, I succeed 3 years ago , to install solaris 7.0 + windows NT and windows 2000 on a quite old PC, although M$ don't recommend to create 2nd pri.partition but actually it's reliable , simply use partition magic to resize a empty space in the begin of your hd, then solaris will recognize the space then use it to install, at last it will install a sun dual boot manager in the MBR then your system will be dual-bootable.
good luck.
