Sounds like a daunting task!The "buy a new drive" option sounds good
It is a bit of work but it will be well worth it. It is so much better working with Windows 7 64 bit. For me it was " Why didn't I do this years ago"
1- Install new 1 or 2 TB hard drive, put old drive in a cool dry place.
2- Format drive into 100 Gig "C" partition and balance to a data partition.
3- Install new OS
4- Update all system drivers
5- Run DPCLAT meter and tweak system for DAW
6- Disable on board sound card
7- Install drivers for Audio interface
8- Install DAW software.
Because all your CPW and Samples are on the other DATA drives you are now ready to get back to recording.