I don't think this is a Windows XP question. I'd try our http://forums.cnet.com/storage-forum
Just a few notes:
1. I'd never believe something "said". I'd read the manual first and if necessary ask the tech support of the maker.
2. I'd never do such an operation without having a very good backup of that 2 TB of data.
3. I doubt if Windows XP will handle a 4 TB disk, but maybe it does if you make it 2 partitions. That's the first thing I would try.
Kees
I'm using a Netgear MS2110 network storage unit, said to support hot-swapping of its HDDs.
It currently has two 2TB hard drives and is configured as RAID1.
My question is, if I want to upgrade to two 4TB drives (maintaining the same RAID config), is it simply a matter of replacing one of the hard drives with the larger capacity one, and when the data has been mirrored across to that new larger drive, then replacing the other drive, so I end up with the two 4TB drives with all the original data?
If this is essentially possible, are there any traps that may result in data being lost in this transfer?
Cheers,
Brian

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic