These are the instructions to root Samsung Galaxy Win I8550 (running on android 4.1.2) using Framaroot Application on Phone itself (this process doesnt need Computer).
Requirements: Your Samsung Galaxy Win I8550 should have atleast 10-20 percent of phone battery to perform the rooting process.
Step 1: Enable USB Debugging on your Samsung Galaxy Win I8550. To enable USB Debugging: Open Settings > Developers Option > USB Debugging > Tick to enable.
(Developers Option is hidden for Android 4.2.2 or above, to show this option Go to Settings > About Phone > Built Number (Tap on it for 5-8 times).
Step 2: On your Device, Open Settings > Security > Device Administration >Unknown Sources (tick to enable it).
Step 3: Download (v1.8.1) and install Framaroot Application on your Device. Once installation is completed you will be able to see the Framaroot Icon in your Menu.
Step 4: Now, Tap on the Framaroot App Icon to Open it.
Step 5: Once Framaroot Application is launched you will be able to see the following screen:
Step 6: In Framaroot, You will be able to see 2 options i.e Aragorn and Galdalf. Tap on the Galdalf Option.
Step 7: Now, you will be able to see the success popup on the Phone Screen.
Step 8: Now, you have to restart your Device.
Step 9: Now your Samsung Galaxy Win I8550 is Rooted. To check whether your phone is rooted correctly, open Applications Menu, there you will be able to see a new app installed, called SuperSU. If this app exist then it means you have successfully rooted your device.
Optional: You can also verify the root status of your device by using the Root Checker Application.
[*] No data loss process: Your Samsung Galaxy Win I8550 Phone Data like contacts, pictures, videos, music and etc will be not affected with this method.
[*] Device Warranty: Once you full unroot your device through SuperSU, you can claim for the phone warranty. In short no need to worry for phone warranty.
[*] Credits: Framaroot Application is developed by alephzain (XDA Developer).
[*] Alternative Method: If you want another easy way to root Samsung Galaxy Win I8550 then see How to root any Android device using vRoot.