NTLDR is missing..?!?

[Jenna0921]

hello. this morning when i turned on my dell XP computer, I received this message;

Loading PBR for descriptor 2...done.
NTLDR is missing.
Press Ctrl+Alt+Delete to restart

and when i do restart, i go right back to that message! :/

I have not changed anything at all..the only thing i could think of was yesterday i installed a webcam for my computer. I am not sure if I have a CD that i can use to fix this that came with the computer???

I do have these disks included with my computer purchase;
*A Reinstallation CD Microsoft windows XP home edition, including service pack 2

*A CD For reinstalling V.9X/56K Data/Fac. Modern software for Microsoft windows.

*A wordperfect Productivity Pack
and

*Dell color monitor user documentation

I really don't know too much about this. I searched on google and I just didnt understand really. If someone could please help me get my computer starting I would be extremely greatful.

jenna