Why is there a password?

I did a windows xp reinstall repair on a dell inspiron 1501. I set up the bios so that it would boot xp from the cd. Then i pressed enter to do a fresh windows reinstall. There were three partitions on the hard drive so i deleted the two that had less space. Then it went through this thing where the drive needed to be formatted. After the drive was formatted I tried to reinstall a fresh new version of windows xp but it told me that there was already windows xp on the drive and that having two xp's in the same partition wasnt a good thing to do. So I decided to do an xp repair on the os that was already there. After it copied the files and did its thing the computer restarted and installed windows. I ran into a snag while reinstalling windows because the computer couldnt find a certain file. It asked if File: D:/i386 was inserted in the drive. I clicked retry and it did its thing but came back with the same error message. Then i opened the d drive and closed it and everything was fine it finished intalling xp. Then i chose english as the language put in the name of the person who owns the computer and crossed my fingers hoping that I had fixed the freaking thing. I thought it was going to work but it came up with windows xp user screen and asked for a password when this computer has never had a password and of course i dont know what the password could possibly be. So if anyone has any insight into this kind of thing then any ideas would be appreciated.

Thanks

 

Try leaving the password blank and hitting enter.

 

that was the first thing i did.