Hi tAyyaba,
Welcome to the community,
This sounds like it could be a Boot issue, however it seems you have followed the correct path so far. In this case I would suggest trying a software repair on the handset to try resolve this issue.
Please see the instructions below.
Here's how to run the repair on PC Companion:
1. Install and open PC Companion then select Support Zone.
2. Phone Software Update.
3. Start.
4. Repair Phone
5. Continue
6. Accept data removal
7. Next
8. Wait for prepare
9. Select Phone
10. Follow the connection steps
And Bridge for Mac:
1. Launch Bridge for MAC without the handset connected.
2. On the Main Window select "Xperia > Repair Xperia Device".
3. Ensure the phone is charged and select "Ok" in the following window.
4. Select Continue on the following page.
5. Wait until the initialising step is finished the continue as below.
6 . Select your model of phone from the list that appears
7. Follow the connection steps that appear, ensuring that you are holding the relevant button down before during and after the connection phase until the update/repair begins.
Let us know how you get on.
