Virtual Partition uses more space than it should-any ideas?

[toptop1200]

Here are my system specs:

Ubuntu 7.10 Gutsy host
Windows 2000 Guest
Virtualbox 1.5.2

The guest partition is 3GB and 'formatted' for NTFS (this is the option I select when running the W2K installer program).
Ubuntu file system is ext2.

Here's the prob...
I have installed W2k and service pack 4 on the virtual partition and have already used up almost 2.5GB of the partition. How is this possible? I know Windows uses a lot of resources but I'm pretty sure a standard W2K and service pack install (about 129MB) shouldn't be much more than 1GB.

I know the virtual file system is not working properly because when I download a file that should be 10MB for example, it ends up taking up approximately 20MB of space on the virtual C: drive.

Any ideas? Is it to do with the ext2 system on the host?

[frank]

This is most likely the NTFS file system of the guest. This is a journaling file system, that is it keeps additional data to guarantee that the file system is still persistent even after a crash.

Note that VBox will allocate a disk block on the first use, that is if the guest is writing to a block which was not allocated previously then this block will be allocated and never (automatically) freed again. The journaling stuff and the fact that a new file will most probably allocate other disk blocks than a replaced file lead to a growing virtual disk image. So your observed behavior is just normal.