My mothers pc is in a boot-up loop

Hello,

my moms pc is stuck in a boot up loop. it starts up and goes to the "select how you wish windows to start" (she has xp home ((so she thinks)) i think it's pro though.) i click start normaly, it goes to load and then it loops back to the select. i click start with last known good configurations (or what ever it was) and it does the same thing. i click start in safe mode. it shows a list of the samwe thing over and over and it just goes back to the same screen. same goes with start with comand prompt, and the same goes with networking. i have tryed booting from the only windows xp disk we have but it's a burt copy of the orignal so i am guessing that is why it won't work. i have tryed the hard drive boot and that won't work. now i have also tryed the boot disk that microsoft web site lets you download but when i ever try it it just says something simular to "failed boot, press f1 to retry or f2 to exit" and then it just goes back to the select screen again. it just doesn't load past it. so i am now looking for a downloadable boot ""CD"" not ""DISKIT"" i need ""CD"" i am hoping that this would work. but if any one here has any other idea of how i can fix it, I WELCOME IT! plus Ctrl-Alt_Del doesn't work, it just makes the pc think that there is no key board. eather reply to this or e-mail me at plvary@yahoo.com thank you.