Dell XPS Laptop / Windows 8 - UEFI And Partitioning

My wife got a new Dell XPS laptop from her employer. A very impressive bit of kit with Windows 8, 64 bit, masses of RAM and many, many processor cores (dreadful touchpad though ). And 1TB HDD.

She asked me to set up it the same way as her existing Windows 7 laptop, so a fun few hours discovering how the charms bar works (before giving up on that and going for Start8) and installing various bits. I then decided to partition the huge drive so the OS and program files are on one partition which can be imaged and restored with Acronis as required while all the jpgs mp3s docxs etc remain safe on the second partition (every computer in out home is set up this way and I've found it to be the best method).

I shrank the partition as much as possible and ended up with 400 GB before immovable files put a stop to that - needlessly large I thought so I installed EASEUS partition manager which I have used with W7 without problem (can you see my obvious mistake yet?) and set it for a 200 GB partition, started it going and popped back five minutes later expecting to find everything as desired. Instead the laptop no longer believed it had a HDD. The current situation is that the machine is pretty much as wanted except the partition sizes aren't as required and no Acronis image has been made.

So, the questions this experience raises are:

1. Did the drive fail or did EASEUS break it? (If it was just waiting to fail my opinion is that it's good to find out so early on and not when it was full of data that hadn't been backed up).

2. Which partition managers are safe to use with the combination of Windows 8 and UEFI that Dell have produced? I'm somewhat nervous of just experimenting on this point.

3. Is Acronis safe to use with Windows 8 and UEFI.