It certainly sounded like a software problem and not a hardware problem when he first mentioned it.. but it looks like he ran RAM tests? And if they failed, it at least means he need to replace the RAM..
To me, it doesn't sound like your computer is dead without repair. At first it sounded like your Windows Installation was busted, in which case you definitely would need an installation Disk to either fix it or re-install Windows. If you don't have one, you're in trouble.. you'll have to find one, or find a way to make one or something.
Otherwise, those "March A" tests and stuff sounds like you have Bad RAM, which can screw up Windows running because, well, if it can't read or write from RAM correctly, it'll crash and you'll get blue screens.
So either way, if you ran those RAM hardware tests that come with DELL computers, and it showed a lot of errors in the DIMM slots, then you need to replace the RAM. It's gone, and there's no fixing hardware.
After you replace the RAM, you'll have to try booting your computer, and only then will you be able to know whether or not your Windows installation is dead. Although I guess you could find out by placing that hard drive in another working computer, and try booting from it.. then you could find out whether Windows still works or not, but that takes a bit of work if you've never done it before.

