Here's the approach I follow:
Disconnect the HDD.
Boot up from the Win 7 DVD.
Wipe the SSD clean using the procedure I give.
Install Win 7.
When you boot up from the DVD, you want to go to a command prompt and then issue some commands followed by an exit back to the Win 7 install routine.
GO TO A COMMAND PROMPT USING YOUR WIN 7 DVD
Booting from a DVD/CD
On some computers, immediately after pushing the Power ON button, start tapping the F12 key and choose the option to boot from DVD/CD.
On some computers, this capability is assigned to another function key.
This is a one-time boot and doesn’t change your normal boot sequence.
If your computer doesn’t offer this capability, then you will need to boot into the bios and change the boot order there so that Boot from DVD/CD is the first choice.
You will need to consult your computer manufacturer’s documentation.
STEPS TO BOOT TO A COMMAND PROMPT USING A WIN 7 DVD
Ø Insert your Win 7 DVD into the optical reader
Ø Power down your computer.
Ø Power up your computer.
Ø Boot from the Win 7 DVD using the procedure applicable to your computer.
Ø When the following is displayed on your screen,
press the key combo of SHIFT + F10.
Do NOT click on Next.
Press the SHIFT + F10 key combo.
You will have a X:\Sources> command prompt.
X: is a ram drive created by Windows 7.
X: contains a mini-version of Windows 7 called a PE (pre-execution environment).
If you do not plan on installing windows at this time, you may now remove the DVD.
If you plan on continuing with an install, then do not remove the DVD.
Execute the desired commands.
Use the EXIT command to return to the Win 7 installation procedure.
Here's the commands you want to execute to wipe your ssd clean:
BOOT FROM YOUR WINDOWS 7 DVD AND GO TO A COMMAND PROMPT
Ø Insert the Windows 7 DVD and close the DVD door.
Ø Power on your computer.
Ø When that very first dialog appears where you would normally push the NEXT button, then use the SHIFT + F10 key combo to get to a command prompt.
Ø The command prompt will be X:>
USE THE DISKPART PROGRAM TO “CLEAN” THE HARD DISK
Type the commands shown, hitting the Enter key after each.
Do not proceed to the next command until the current command is finished.
· DISKPART (the command prompt will change to DISKPART>)
· LIST DISK (this will list the disks present)
· SELECT DISK 0 (assuming disk zero is the desired hard disk)
· DETAIL DISK (this will show you info regarding the disk you selected)
· CLEAN ALL (this is the command to write zeros to entire disk)
This can take half a day for a 2 Terabyte disk.
· EXIT(this will exit you from the DiskPart program)
· EXIT(this will exit you back to the Windows 7 install program)