If u uses Window Vista Enterprise or Ultimate and want to use the BitLocker Encryption, but your computer does not support the TPM module. In that case, u may use a USB stick or a memory card as the key medium, then u’ll have to force Vista to accept something other than the TPM module.
Steps are:

1. Goto Run and type ‘gpedit.msc’ and press Enter.

2. Now goto ‘Computer Configuration > Administartive Templates > Window Components > BitLocker Drive Encryption’

3. Now open up configuration windows by clicking on ‘Control Panel: Advanced startup Options’

4. In the ‘Settings’ tab select ‘Active ‘ and ‘Allow BitLocker without a compatible TPM’.

5. After clicking Accept , the BitLocker wizard (in Control Panel) shows the newly added option.

After this , do rest of the setting according to the instructions given in the control panel. Before encrypting any hard disk, make sure u have take a backup copy of ur disk.

Window Vista has a built-in Visual Basic Script which allows its user to increase the trial period of vista by 30 days. u can use this script a total of 3 times , hence extending the trail period to upto 120 days. The process is known as "Rearming".

Usage of this script will not result in any violation of Window End-User License Agreement.

How it works:-


1. Goto Start> All Programs>Accesories>Command Prompt

2. Right click on command Prompt and click "Run as Administrator"

3. It will redirect u to this location

C:\Windows\system32

If not, then move to this location.

4. Now type the script and hit enter.

Script is:
cscript slmgr.vbs -rearm

5. The command will take some time to execute and will ask u to restart ur system.

After restart u will see ur Activation period again to 30 days.


Note:-

The script will not work if the activation period has ended and vista has entered into lock down mode.