My computer verry slow.. i want format my computer

You can format by doing a fresh install of Windows. What operating system are you using? If you are using Windows and you have the windows installation disk then you can easily reformat your HDD. All you have to do is go into you BIOS (When your pc starts press <F2> repeatedly. When your BIOS is up look for your (BOOT Partitions). With the Windows disk in the disk tray it should show up on the list of partitions. Move the disk drive so it adds the Windows installation disk as the main boot partition. When you are done with the bios settings restart your pc and the installation disk should prompt you to install a fresh version of windows on the next startup. If you have Windows hope this helps :)