Where has the disk space gone?

[Nick]

Hmm, it's different in my 64-bit Win 7; you can select a total size allocated to backups and when that is reached, older ones are automatically deleted.  I don't see any way of viewing the list of backups and dates either.  Although as I recall, if I did want to restore to a previous point, the list would come up then. 

There are 6 different versions of Windows 7; Starter, Home Basic, Home Premium, Professional, Enterprise and Ultimate.

All but the Starter version are available in 64-bit as well as 32-bit. The six main variants are all different - sometimes fairly radically!

There is no functional difference between 32 and 64 bit versions - only the amount of addressable memory changes.