Why is this error in Vista?

*I'm still not sure how this happens, but some people are reporting getting the error message while using Windows Vista. The odd thing is that Windows Vista uses a new boot loader, and not NTLDR.
*Email I got 1 day ago:
Saw your online comments about 'NTLD is missing'. Have you had time/opportunity toinvestigate Vista? If so:
System: Dell Vistro 200 (small case, core2duo, no floppy, one 320GigHD, Vista Basic, no discs).
Problem: Will not boot. Shows Dell splash screen then 'Intel bootagent GE v1.2.50 PXE-MOF'Then: Exiting Intel boot agent'.Then: PXE-E53: no boot filename received.Then: NTLDR is missing. Press Crl+Alt+Del to restart.When I do this it just goes back to the same screen.I have tried 3 boot discs (+ your own, I burnt it on my Mac (withwhich I have more experience),I am emailing from there. I have tried a flash stick but it just says'None system disc, press any keyto continue'. When I press any key it just repeats the message untilthe screen is full of '...press anykey.....press any key.....press any key... I have tried changing theboot in BIOS but it won't let me,always reverting to default, even when I have selected CD & pressedF4 to save & continue.
I have no Vista discs (it was pre-installed). I tried an XP installdisc that worked on my old PC butthe Vistro just said that I had a newer OS installed & would not letme access it.
I think Dell has done something to 'protect' Visa (it's trying toforce everyone to 'upgrade' to Vista).This situation happened when I tried to uninstall Vista. I have triedit & don't like it (too 'nannying').
All I want to do is get rid of Vista, reformat the HD & install XPbut it won't let me. Any help wouldbe appreciated.

*I replied with:
Unfortunately no news on Vista yet :(Try it anyway, you might bring up an old windows xp you can use to fix the vista install with

*And then later replied with:
If you really do want to go ahead and roll back to XP. You need tobackup your data, then do a format and install.

*I'll have to try and get some more info under my belt and see what's going on. Sorry :(