Weird Windows 7 post-upgrade phenomenon

I have a user who upgraded their Dell Inspiron 6400 running Windows Vista BUSINESS to Windows 7 PREMIUM (I know, but no one consulted me first). I don't know how much of this was done intentionally or out of ignorance, but they installed it to dual boot Vista and Win7. For some reason, or maybe as a consequence of selecting dual-boot, Windows 7 is storing all %program files% data and %my documents% files on the Recovery Partition (drive D:) instead of on the boot partition (drive C:). Naturally, the recovery partition is now maxed out and there are 30GB free on the boot drive. Anyone know how/why this happened (pilot error notwithstanding) and how to correct this, short of reinstalling everything from scratch (I already figured that out!) Thanks.