Cleaning hard drive to start fresh. New to this!

Okay, I apologize because this has been answered a million times but when it comes to this portion of computers I am a complete novice.

I recently got a computer from my dad, a while back he had updated to Windows XP but for some reason old files and programs remained on it. When he got a new pc he just put this one aside and forgot about it until now when he has wonderfully gifted this problem to his kid...of course.

I bought Windows XP Home Edition to put onto it. However I cannot get it to erase the old files. When I try to install it the program allows me to install it over the current "partician" but won't allow me to delete and start new. It gives me an error message saying that it cannot delete the old files? I apologize for not having more specifics but to get them I'd have to actually go through the reinstall process all over again right now and hoped someone might be able to help me without the information.

I just want to know if it is possible (and if so how to do it) to just completely clean off the hard drive and then install my new version of Windows. I have read many of the posts on here but I am a little younge for things like DOS and most of the other lingo used. I am willing to learn but obviously would like to fix my pc and get it running properly before I concentrate on educating myself further if it is unnecessary to do before hand.

So any advice for the new kid? Thanks for any assistance.

-Seth

 

Thanks, I have it all up and running now. I think the BIOS was my issues. Never would have thought of it on my own. Now it makes me wonder if it's what my fiancee did wrong on her laptop. I'm going to have to check out her system tomorrow.