Windows Inherited an HP - can't enter the BIOS

I inherited an HP Pavillion XT958 with a 1.8 ghz P4, 512 MB o' RAM, an 80 GB HD, and an ATi 9700 Pro. Here's my issue. I want to install a fresh copy of Windows XP Professional on to the HD. I was able to boot the computer into XP Home and begin installation, but as you all know, when you install Windows that way, I does not let you delete all partitions on the HD. I want to enter BIOS and change the first boot device to CD-ROM, so that I can delete all partitions on the HD, but I cannot figure out how to enter the BIOS. When I turn the computer on it goes HP Logo ----> select b/t XP Pro and XP Whistler Home ----> XP Logon screen. Hitting Del doesn't solve the issue. Please help. Thanks.

 

A quick search on HP.com yealded this: http://h10025.www1.hp.com/ewfrf/wc/...us&dlc=en&submit.y=4&submit.x=9&lang=en&cc=us all you could ever want to know about the Pavillion XT958.....