Don't buy a Mac. I'm on my fourth one at work and they've all been crap. I'd never allow one in my house.

I've never dealt with Dell, but other PCs I've seen come with the rescue disk that gives you the option of re-installing the OS without reformatting and losing your work. That may be an option.

Alternatively, any decent computer shop should be able to remove the hard disk, set it up as a slave in another machine and extract your data.

Good luck.