Windows XP pro cycling startup

I have had my computer for 7 years it is a dell dimention desktop 2gHz 2gb ram 2 hard drives. I went to college and they reformatted my machine with windows XP pro. The other day i went to start up my machine and it went to the loading screen as soon as it was done loading the "blue screen" came up and it shut down immediately and restarted. Now it will just cycle like that.

My roomate gave me his old computer because he upgraded so i took all his old stuff and kept my hard drives. Took his motherboard ram graphics card processor and bought a case 600W power supply and a DVD burner. Started it up and had the same problem. He also gave me a legal Windows Vista UPGRADE CD. i tried booting from that CD and it said i needed to go into windows first!!! ughh.

I am strapped for cash since i am taking a break from school. I tried safe mode last known good config all that and nothing works. i think a startup file was deleted because i had no anti virus software on it at the time but i have no Windows xp pro cd to repair the machine with. i wouldnt mind reformatting i have nothing on the hard drives i care about but i dont have $100 to spend on an OS.

Is there anything i can do cheap to get my machine running again?

 

I still have the CD key on my Dell for Windows XP home so i just need the CD if that makes a difference

 

If you have nothing to lose on the hard drives, formatting is often the best option.
It is possible that one of your hard drives has /is on its way out. When more than one hard drive is connected, and one fails, this can cause the problem- you may have to install on the second hard drive, by formatting.
Have you tried with one hard drive connected ?
Retry both hard drives, seperately, if necessary- I assume the second hard drive is for documents etc:
Otherwise, If you have another spare hard drive- no matter how small, it could be worth trying to install your XP on that -If it is only installed on one computer, you should be o.k- choose to activate by telephone, do so by telephone, and then when asked, how many computers it is on- SAY NONE, on the automated service.You will get a list of numbers to insert, an you are up and running on XP .

 

like i said id love to reformat but i dont have the CD or the 100 bucks to buy a new copy off ebay or tigerdirect. but i do still have the XP home CD key off my dell although i dont know if it will work since its a new computer except for the hard drive

 

its cool my mom dug up her old CD and i reformatted and i had a friend have a spare vista upgrade CD so now im sitting really good thanks for all the help guys