I am unsure where you stand regarding your claim but If I were you I would get XP on the laptop as offered by them.

The statement about it running out of support is slightly un-true. XP will not be avalible to system builds as of the end of this month but support for the operating system will continue until 2014.

http://www.engadget.com/2008/06/24/microsoft-promises-to-support-windows-xp-until-2014/

Your right regarding vista as it is a very demanding OS and needs at least 1.5Gb to run smoothly as it will us 700mb of memory doing nothing. Once the laptop has been put on XP you will notice it fly. If you know the rest of the spec of the old and new laptop I can let you know if it should be better than your last one or if they're given you a bag of spanners.

In regards to your lost data, I don't think NU or the assor can't be blamed for the portable Hard drive not working on your machine, and to be honest all important data on a laptop or desktop should be backed up on CD's or DVD's. All I can say is BACKUP BACKUP BACKUP, I am pretty sure you'll remember this from now as everyone losses important data at some point and learns from their mistake. If you need to get your data of your laptop the best bet is to get hold of a 2.5 inch hard drive caddy (shouldn't cost more than £10) and you put the broken laptop hard drive in the caddy. Take it to another computer and copy the important files from the harddrive to the spare pc. Put the laptop Hard drive back into the laptop and then send it off.

Then get NU to put XP onto the other laptop and get them to upgrade the RAM as promised, then get your old files of the other machine and copy them to your new laptop. I would avoid a cash settlement as they will give you what the laptop is worth now not what you paid for it.