How can I reformat a hard drive without a cd

I have a PC with Windows XP Professional and it has an inoperable virus.I don't have cd / dvd drive. I want to format the hard drive and re-install the windows XP. Not sure if this is possible without the CD....Please advise.

If you have restore partition then there should be an option at boot up that will run the restore program. This will reset your computer to the state it was in when you first got it. For doing this, click Start, click All Programs, click Accessories, click System Tools, and then click System Restore.

Otherwise go to Control Panel/Administrative Tools/Computer Management/Disk Management and select the drive, right-click and format. when it is done, you will see Unallocated space - right click again, select New Partition, click Next, assign the letter and click OK.

Try in safe mode by pressing F8 during boot then go into safe mode choose safe mode with command prompt type "format c:" that will clean it then start with the install disk in it. Or you can format it with usb drive. Set the usb drive as your boot device and boot the PC with the XP disk. Run the installer and it will give you the option to format the drive as part of the installation process.