Lisa:
There is a workaround for this but I'm not sure it's practical in your case
since it depends upon a number of factors and we don't have that information
at hand. So let me pose the following...
1. Re your 250 GB USB external HDD (it *is* a USB device, right?)...
Is it a commercial single-unit product? What I'm getting at is can the HDD
within the enclosure be removed (uninstalled) by the user (you)? Or, for one
reason or another, is this impractical? If it is impractical, read no
further.
2. But if the HDD in the USB enclosure could be removed, it could then be
installed as your primary internal HDD in place of your current 30 GB HDD.
But before doing so, using a disk imaging program such as Acronis True
Image, you would "clone" the contents of the 30 GB HDD over to the 250 GB
HDD. You could also use a disk copying utility that's nearly always freely
available from the website of the manufacturer of your HDD - the 250 GB
one - to undertake the same disk-copying process.
3. But we don't know if your 250 GB USB external HDD currently contains
programs & user-created data that you don't want to lose. If you cloned the
contents of your present 30 GB HDD to the external HDD as indicated above,
then *all* the data on that latter drive would be "gone with the wind".
(Unless, of course, you would first save whatever data is important to you
to some other media with the intention of later transferring such to the 250
GB HDD after it is installed as an internal HDD.)
(Keep in mind that a disk imaging program such as the one mentioned is a
valuable program that you can - and should - use on a routine basis in the
future to back up your entire system).
4. So, if up to now the above is "doable", then you (or someone) would need
to install the 250 GB HDD in your machine (following the disk-cloning
operation) as your primary HDD in place of the 30 GB one. And, if practical,
install the 30 GB drive in your USB enclosure.
As I've said, I really don't know if the above operations are practical for
you to undertake. Perhaps you have a friend/associate who is reasonably
knowledgeable about these things. It's really not a terribly complicated
process but obviously some knowledge about PCs is necessary to bring this to
a successful conclusion.
Anna