If you believe your Android phone or tablet has a virus then the good news is it's really easy to delete. Here's how to remove a virus from Android. Also see: Best Android antivirus
First of all, it's worth pointing out that it's unlikely that your Android phone or table pc build has a virus. What you're more likely to be seeing is an ad that wants to convince you Android is infected and you need to download an app, or a dodgy pop-up, or perhaps your device is just misbehaving. But viruses for Android do exist. If you're sure your device has one, here's how to remove it.
All Android viruses are delivered via apps installed on your device, so if your phone or tablet doesn't already have a virus, the best way to avoid it getting one is to never install software outside of the Google Play app store. Open your Settings menu, look for the Security option, then ensure the option for Unknown Sources (allow installation of apps from unknown sources) is disabled. Also see: Security Advisor
If you're determined to install an app from outside Google Play, do your research. Check its permissions (does a video player really need to see your contacts?), look online for reviews and have a good look at the developer's site to see what else it offers.
You can also install an antivirus app, and plenty of free Android antivirus apps are available that are able to detect and remove malicious apps, for example 360 Mobile Security, Avast and Lookout. These all include an app scanner that will seek out anything dodgy, but note that these apps can also trigger false-positives - reporting an app you've been using for months as malware when you know it's fine. In most cases you can simply ignore these alerts.
If you believe you already have a virus on your Android phone or tablet - perhaps one that is resisting your attempts to uninstall the associated app or even let you bypass the lock screen - a factory reset will remove it, returning your device to its out-of-the-box state. But doing so also means you'll lose everything on your phone that's not backed up. Instead, follow the below steps to remove a virus from Android.