How to delete adware from my S4?

[asbj]

Hi, first time posting in here

I misused my phone and installed an infected app from the Play Store.
After that, I was able to delete most of the ghost push malware installed on the phone using the app Stubborn Trojan Killer.
For months I have used it with 2 irremovable adware apps but my phone gets slower, more glitchy and the battery drains faster day by day. Since yesterday, the process System UI crashes every 5 minutes or every time I hold down the home bottom. All of that is driving me insane.

Also, this phone was from my best friend who rooted it so my question is: will flashing the firmware and installing another version of android repair the damage?
Please, if someone knows how to solve this, tell me what to do. I will the eternally grateful.

These are the trojan and adware apps:

 

[spagman]

Google play Store is usually very good regarding infected apps... Are you sure that's the way your phone got infected?

Anyway.... You should make a backup of all your contacts /pics / videos and other data.... Do not back up the apps / data of the apps that you think are infected, same thing for your web browser...do not backup / restore your browser data.

After you made all your backups you should try a factory reset from recover mode.

After the factory reset restore your contacts / settings etc. And hopefully you're good to go.

 

[asbj]

Google play Store is usually very good regarding infected apps... Are you sure that's the way your phone got infected? .

Yes, I am completely sure. It happened after I tried to download some pokemon go apps from the Play Store.
I already made a factory reset and everything was gone but the apps stayed. I suppose I need to flash the firmware so can you tell which is best current rom for the GT-i9500?

 

[spagman]

Hello,
Flashing your phone is risky and can lead to a permanent bricked device.

Your best bet is to search the forums for firmware and procedure.

Thanks