i keep getting clean hard disk messages in my pc am running windows xp i deleted fat and fat32 can i clean still most of my hard drive in safe mode and is it safe please answer i need help with this i know there are knowlegable people here who can help most of the hard drive thats almost full is c

I want to install a new clean OS of Windows XP on my computer.

How I usually do it is to boot from the OS CD then format the Hard drive then install a new Windows.

To do this i usually would change the priority boot sequence and put the CD-ROm Drive first… but this time it doesn't work?

I have the motherboard
INTEL D865GLC

It happens like this on all of my computers running this motherboard.

The computer will boot off the CD ONLY if there is no operating system currently on the Hard Drive.

But there is and and want to REdo it.

Is there a way to fix this, or is there another way to format the hard drive and then install a new OS?

I can see the drive in the device manager and it shows up in the BIOS when I first boot up. When I run the Western Digital diagnostic software it detects the hard drive as well but it wants to erase the data in order to install it. Is there a way to get the data off the hard drive before it is installed or otherwise get My Computer to recognize it?
Thanks

im trying to delete junk from hard drive whats the easiest and best way to do that? also… does overloading on memory restart the computer?? i inserted an extra 250 mb of memory on the 500 that it has already…..how can i check this out…??
but i dont have or i lost the windows xp cd… any other way???

My computer is running slow and bogged down. Its about six years old and I was debating just wiping the hard drive and starting over but, uggh, so much time and lost pics/music. A friend suggested using a registry cleaner to make my pc run faster. Anyone know of a really good one, and if possible, free?