In order to hard reset a Sony Ericsson WT18i, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Sony Ericsson WT18i device will be brought back to the default configuration of a brand new device.
1. Download and install the PC Companion on your PC.
2. A new window with 4 options should appear.
3. Click Start.
4. Installation process should now begin. Afterwards, a Phone / Tablet Software Update window should open.
5. Continue by clicking start and repair my phone / tablet. Confirm anything that comes up.
6. When able to, select the model of your phone.
7. Follow the on-screen instruction. Done.