Before start discussion on format a computer without cd, we know formatting is easier and faster when having severe problems with their computer that could possibly be caused by a virus, to delete the partition and reformat the hard drive because it ensures that the virus is gone. Reformatting the hard drive is like wiping off a chalkboard and starting over with a clean surface.
If you have used your PC for a long period of time and it has become slow and bogged down, reformatting can help make your computer seem brand new again. If a computer is reformatted in this manner, caution should be taken to reformat all hard drives attached to the computer since the virus that infected the machine could have infected files on other hard drives, not just the primary drive.
You can also use the built-in software on your computer to format a hard drive. There are a number of tools to help you do these things. Formatting a hard drive causes all of the data on the drive to be deleted, so don't format a hard drive unless you've backed up.
2 Tips For Format A Computer Without CD:
1: Format using command prompt
To format using command prompt click start ->All Program-> Accessories-> command prompt then
type format <drive letter:> /fs:ntfs (fs specifies the type of file system) example: format d: /fs:ntfs
(you can also access command prompt using run and type 'cmd')
2: Format using Computer Management
Log in as an administrator on your PC. Then start -> control panel-> Administrative Tools-> Computer management then select Disk Management located in storage section, then just right click on drive that you want to format and select format option.
Using this method you can't format primary drive If you want to format primary drive also you can follow steps in Step by step XP Installation. Both methods are simplest ways to format hard drive excluding primary drive. I hope this 'format a computer without cd' short tutorial help you to repair your PC.