OS ->Window8
Laptop -> Dell Latitude E6430
Problem:
Everytime after I restart, the saved password of the Wi-Fi is wrong(it's my old passworld). I have to manually enter the new security key and it is not retained after restart.
Tried attempt: I've already tried forgeting network, delete profile using netsh. didn't work.

This issue can be caused if Windows 8 not saving your network security key, or reverting to some old key, the solution is as follows:

Try create a wireless network manually.
On the Desktop screen, right-click the Wireless Icon located on the lower right hand corner of the screen, and select Open Network and Sharing Center.
Select on Set up a new connection or network and then click on Next.
Select on Manually connect to a wireless network and then click on Next.
Manually enter the required credentials for the wireless network you are trying to add, then click on Next.
You will have to enter the following credentials :
(i)Network name (SSID). (ii) Security type. (iii) Encryption type. (iv) Security Key (password, passphrase).
You will get a confirmation that the profile is successfully added. Restart the computer and check.