Hacking s60v3 is as important as installing windows in your PC. If you are a common user and you just want your phone for calls/sms, then don't read this tutorial its not for you yaar. :)
With this tutorial you can install so many uncertified but very useful applications. For example almost all python applications are not certified.

There are so many tough and rough tutorials on web to get rid of your s60v3 phones Certificate Error, i wish to give you more athentic and easy tutorial to hack your s60v3 system.

1. Installing X-plore

First you need to Install X-plore signed in your mobile phone.
Then after installing X-plore, press 0 then check first four checkboxes and press back.

You can download it from here

2. Moving Special Folder

Download Special Folder then open it with X-plore and Extract the folder .Sys into Drive C, after extracting this, folder .Sys will be vanished from C Drive now you have to restart your phone.

4. Installing Rom Patcher

Download rompatcherplus.sis then install it. Please note, you have to install it on Drive C aka Phone memory
its signed version, hope you can install it. Then again restart the phone. :)

5. Applying Patch

After installing Rom Patcher, open it. You will see so many patches here! Click on Open4all.rmp after clicking on it, patch will be applied

6. Replacing installserver.exe

Open Xplore extract the file installserver.exe the appropriate type of your phone to:
C:/ sys / bin
download installserver according to your phone.
installserver-for-fp1.zip
installserver-for-9.1-9.2.zip
installserver-for-9.3-9.4v2.zip
then must restart your phone.

7. Counting

I missed counting in Steps. :D

Dealing with Expired Certificate

Simply change your phone date to previous months or years, the try to install application again.

Note

I am not responsible for any damage, try at your own risk. There will be no problem if you try as i wrote.