My current desktop 2 HDD 1st HDD has been partition as C: and D: 2nd HDD has been partition as E: and F: My XP OS is installed on C: How do I format only C: and install refresh XP .

When you run XP setup from the disk, you can pick the partition you want to format/install to (in your case, the c drive partition). Reboot the computer with the XP setup disk. Your cd-rom needs to have boot priority over your hard drives. If not, usually F12 will let you pick your boot device.

Back up any data you wish to save to remote media Consider ntbackup Make note of the sizes of partitions or drives you have now just in case. Download Microsoft network installation of SP3 and save on CD or usb flash. Make note of any drivers you may need. :Place xp disk in cd tray Set bios boot or select boot option at boot for cd. Boot and when you get to drive part of installation, you delete the C drive ( or partition that is called C) and then normal install. Apply SP3 before you do anything else. Playing to the angels Les Paul (1915-2009)

disconnect the 2nd drive's power so you don't get confused as to which drive. Might want to consider wiping out both c and d to then use the entire drive for xp

perhaps you should also use the files & settings transfer wizard to save settings. Use autostreamer to integrate sp 3 or nlite to do the same. UK MP's are thieving scumbags. EU members are worse.

Also, I suggest you look at the type of partitions D,E,F are. If any of them are marked as dynamic then you will lose all data on them if you format C. Look for that information in Disk Management. Control Panel> Manage> Storage> Disk Management. One other thing to note. Any programs installed on any of the other partitions will not work after the re-install and will also need re-installation.