double click my computer right click the drive, select properties.
See what is says is total and what is free.
If it says the total is not 71 gig then the partition does not use the whole disk. You need to adjust the partition size. Partition magic can do this without data loss (most of the time) or windows administrative tools can do it (not sure if windows will wipe the existing data though).
If the drive total is 71 gig then your file allocaiton table may be corrupted or you may have a humongous bad file.
double click my computer right click the drive, select properties then tools then check now. It will probably tell oyu it can't and you have to restart to check. Restart if it says that. It may say bad "stuff" found. It will save the junk to a file called file000x.chk in the root directory, something like that. (My memory is going
from old age.) Then delete that file Note it may be humongous!!