the process you're talking about is known as total hard disk format. If you do a total format, the major consequences will be loss of data (if you forget to backup ur data), u hav to reinstall opersating system for eg. windows xp, or whatever u like, you have to insatll all necessary softwares like motherboard drivers, ethernet and graphic card drivers, audio and video drivers, ms office, nero, and all those other programmes which you think, you need, hav to install a good and updated antivirus.
So if you hav taken care of all those issues, then you can start formatting ur lapi's hard disk. For doing this, u'll need a windows xp or any other operating system's bootable disk.
First of all insert the disk in cd rom and restart ur lapi. configure bios settings to boot fron cd. Generally you can access bios settings by holding down f8 or delete. Now prompt will ask you to press any key to boot from cd. So hit any key. The setup will configure ur hard disk and will begin installation. Let it load all necessary files. After loading all necessary files, ur lapi will reboot. After reboot don't do anyrhing till the installation screen appears. DON'T PRESS ANY KEY TO BOOT FROM CD THIS TIME. Now windows setup will ask you to either install a fresh copy of xp or repair already installed windowS.so select install a new copy of windows. After this setup will search for already installed windows, and will ask to repair already installled windows or install new. So install new. When you select new installation, swtup will prepare a list of available drives. Here the real process begins. Here first of all, delete all the available partition. For deleting a partiton, read the instuctions on setup screen. After deleting all the partitions, create new partitions according to ur specifications. Here basic knowledge of size calulation will definitely gonna help you. Just remenber, 1 gb=1024 mb. So if you want to create a 20gb drive, then 20x1024=20480 mb. Put the out comewhen setup ask for size of drive you wanna create. After creating install the windows. After installing windows, first of all,even before installing drivers, install antivirus, update it and then install all other necessary softwares.
Genrally a disk containing all the necessary drivers comes with the lapi at the time of purchase.
Hope you find this info usefull and if you do, please vote it for best.