Give us any information that you can about the system. Is it a brand name? If so give us not just the brand but the model number. Do you at least know the size of the disk? Give us that too. If not a brand name, was it made by a local computer store? Did you make it yourself? (I build up all of mine and those for many friend but that doesn't seem likely in this case). What do you remember seeing under "my computer". You almost certainly had a "C" partition. Do you remember having other partition letters for hard drive partitions? (There will also have been a drive letter for the CD or DVD drive, do you remember what that letter was?) If you remember other hard drive partitions do you recall how large each of the partitions were? The total should approach the total size of the disk drive, although it will not match it due to the absurd way hard drive makers rate the size of their drives and perhaps because of space unused in the formatting process. I guess I should also ask if the computer has only one hard drive or if there are multiple hard drives there.

And I really hope that you don't reply that you had something called a RAID array. That would explain a lot of your problems now.