Complete XPpro re-install: so why can't I get started?

Okay, so I have my original Dell disks (XPpro, drivers, utilities, etc) and I've backed up all my music, photos, email, drivers, etc.  and I'm ready to go !

So I insert the XP disc and it says it can't reinstall directly from inside windows (understandable)  and that I should close Windows and boot up with that install disc.

So I try that,  but it won't read the windows install disc: it just powers up Windows like normal.

 

Okay,  so I go into my setting (F2) and I go to try to make the disc drive the first device, and ..........   can't get into that setting to change it !    something about logging in first as administrator and changing the setting  to allow me to modify the set-up settings.

Well,  there's an administrator password in there,  which I'm supposed to know in order to make these changes,  but I don't know the password.   I never put a password in there in the first place,  as far as I remember.   

 

I bought this Inspiron 8600 new, almost 3 years ago,   and it's time for a complete reinstall:   I'm getting lots of blue screens,  etc.

 

So how do I get into these bios settings without the administrator password???

 

or,  more importantly,  how can I boot directly from this XP reinstall disk???

 

Thanks.