Hey there, what do you mean by restart. if you mean reboot your phone then you can easily do it by pressing endkey longer in the home screen. if you mean hard factory reset follow these steps.
- switch off your jiophone first. don’t do it while charging incase it will not work.
- then press the end key and center key together untill a black screen appears
- afterwords release the end key but hold the center key
- after few seconds, a white triangle with ‘!’ sign will appear.
- then release the center key and press end key one time.
- a page will appear with options like these-
- Reboot System Now
- Reboot To Boatloader
- Wipe Data/Factory Reset
- Wipe Cache
- Update From SD Card
-Update From ADB
- Check System Partition
Just press up/down button to switch between options then select it by pressing end key.
You need to select wipe data/factory reset & wipe cache.
Warning this will remove anything from your phone and make your phone newer like when you buy the phone.
Hopes this helps. Have a good day.