Check all connecting cables that are attached to your TV, such as HDMI connectors, etc. Are they all connected properly? If that doesn’t help then go into your TV settings using the remote control and choose to reset to default settings.
You’ll need to identify which model G4 you have and then have a look here: https://everymac.com/systems/by-capability/macs-with-secondary-display-support-dual-mirroring.html Update (10/02/2018): https://everymac.com/systems/by_capabili...-with-secondary-display-support-dual-mirroring.html
It’s very likely you can get a replacement WiFi card, but Ethernet is integrated into the motherboard and is not independantly replaceable. Before you invest in any hardware changes, could I suggest running a full anti-virus sweep using the likes of Malwarebytes and AWDCleaner? Just to rule out the possibility of a coincidental virus attack on a stormy day.
Can you connect a mouse to this tablet? (a keyboard would be okay, but just take longer) We are going to need to right click Start and open Device Manager to see if it is just a driver issue. Any USB mouse will do if you have an adapter to allow it to connect to your tablet.
As you’ve only just installed it, Windows 10 is still ‘getting to know’ your computer. So, go into Settings, then Update and Security, and click on “Check for updates”. I think you’ll find that Windows 10 may fix this one itself after a little while of settling in. Alternatively, if you like doing the techie stuff yourself, then right click on Start and choose Device Manager. Do you see any errors listed there, especially anything related to the USB? If so, drop by here again and tell us what you see.
Go into your email app settings and change over what time period you want to see emails for. For example, you may only want it to download emails from the last three months, one month, or week(s). If you are using something like a GMail account or similar, then your older emails will still be available via the website. Also, you can change a setting telling your email app not to automatically download attachments. As for Facebook, I find the website easier to edit than the app. So, delete what you don’t want from there and your app should synchronise with that.
Don’t be tempted to keep ‘Cleaner’ type apps running in the background. Install a good one, like Ccleaner, clean out your tablet and uninstall that app when finished. If you just want to give your tablet a quick clean to improve performance go into your settings and find Storage, then clear CACHE only. Get an SD Card, Class 1 (or 10) at least, and change settings to store pictures and other stuff there instead of on your Internal Storage. You might even be able to transfer apps you have installed to that SD Card if your settings allow for that. Certain games demand a lot of your tablets resources even when you aren’t playing them - so install an app called Greenify - this will allow you to force close multiple apps you don’t want to have running in the background while doing other things. Greenify will force close apps you preselect when the tablet goes to sleep, or when you tap on the Greenify Widget.