Q&A for How to Detect Malware

Yes, malware can cause this to happen.

It wouldn't be directly affecting the battery, but a virus or malware could be increasing the amount of processing that the phone's processor is having to do by adding additional tasks running in the background on the phone. And that would reduce your battery life by drawing more power from it.

Try using an Android malware detecting/removal tool such as Kaspersky internet security for Android, and slow internet loading times can be symptoms of malware like Trojans and/or they can be WiFi issues.

Ransomware is a type of malware that encrypts your files and asks for money in return for your files back. That steals your money unless you use a malware removal tool and then a ransomware decryption tool.

Sometimes, for example some malware can remap keys so an A might type an = sign and a Q might type a Z.

Malware can access deleted history if it has a built-in file recovery tool. Malware often hides in everyday download and innocent looking files. Malware can also be somewhere on your computer and add some malicious code to one of your existing EXE files or something else (even what you might think of as a RTF or JPEG file!).