Hello,
I've been away for a long time and saw that nobody has chirped-up about this yet.
re: data transfer, you should have NO trouble with that.
re: voltage. Most power supplies, on PC's, usually have a little red/orange voltage selector. All that is then required is a mains plug for your country of destination.
IF you don't see a voltage selector on your machine then don't panic. - Either use a suitable step up/down transformer (depending on original power requirements and origen of computer) - OR - once you've make the move, find your local computer shop and purchase a new power supply for your PC. (They're not much more than $35.00 and require 4 screws and 5 minutes to install yourself!) <----or get the shop to do it for you!!