Cheaper solution is to get a second hard drive an put it in your
computer as a slave....
yes you could xcopy your drive to some backup device then repartition
and plop it back - that would take alot of work and involves
DiskCopy/Ghost like software and has great risk. (Run Defrag first -
Plus you may still need dual partition the drive to put your boot files
back in place.) Backup everything first!
I don't know how much access you have, but another harddrive (100GB
from bestbuy.com about $50 - cheaper that software. You could install
a used, smaller hard drive and you'd never know the difference. Put
just Postgres on the second hard drive (FORMAT IT NTFS FIRST).
hope it helps
Troy H