SYSTEM TOOLS

Boot Disk(in Windows)
Use a floppy disk to make a boot disk. After inserting the disk into the floppy drive,
click Start/Settings/Control Panel/Add Remove Programs/Startup Disk.
Once the disk is made, go to Windows/Command folder and copy fdisk and format utility to the boot disk You just made.  These are the two utilities most used by a systems tech to reformatt a hard drive. This disk should only be used after any files You may wish to preserve have been copied elsewhere as they both delete ALL data and prepare the hard disk for reinstallation of a clean operating system.

Memtest x86
One of the most useful Diagnostic Tools
Memtest86 is thorough, stand alone memory test for x86 architecture computers.
BIOS based memory tests are only a quick check and often miss
many of the failures that are detected by Memtest86.
Cloning Utilities
These Utilities make byte for byte images of hard disks or partitions.
Extremely useful for transferring data from one drive to another and 
making backups of a perfect Operating System once all the drivers,
software, and personal settings have been installed and configured.
Norton Ghost   
Drive Image 

Hard Drive Diagnostic Utilities
These Utilities are Proprietary.  In other words,
You need to choose the one specific to the brand of
Hard Drive You wish to use it on.  They contain various levels
of diagnostic utilities, and Low Level Format or
Zero Fill Utilities.  These are useful for restoring a Hard Drive
to the state it was in when it came from the factory. 
They will totally and unrecoverably erase any data on the drive
 including partition information and boot sectors.  This is one
of the primary uses of these utilities for security reasons.
The drive will have to be repartitioned and formatted again before use.

SeaTools
For Seagate and most other Drives

Fujitsu
Utilities for Fujitsu Drives

Western Digital
Scroll to dlgdiag.exe and download. 

Startup CPL
A utility for disabling TSR's