Either your lucky and a wire is loose, (power, or ide/sata) at drive or mother board. Or the more likely. Dead hard drive. This happens more often then you'd think. Drive may still spin up and make noise also, it just doesn't access data any more. You can usually tell this when it makes a repeated pattern of clicks. This is the drive head trying to find it's starting point to put it plainly. Anyway, unfortunately , if it's the later you need a new boot drive and a Windows restore disk. You can use about any size drive you want, this is where people often use smaller SSD drive for fast boot and add another slower but Huge data drive for media. You can usually get a system restore disk from the manufacturer of your computer. If not available there are instructions to how to create one on the windows website, using another computer to create a bootable USB that will load everything needed to your new hard drive. Hope this helps.
It's probably a screwless case, this is preferable in assembly for cost and ease of assembly. Looking at the pictures I would take a best guess on where to try a prying tool. Probe around any seams you find and gently lift them. They should release if it's a snap together case. Start with the back.
This looks like a popped diode. Any electronics repair shop could fix. The big question is if there is another problem or short that caused this to fail. Start by trying to identify the number on the popped one. Then search it out. Make a few calls to local shops. https://www.build-electronic-circuits.com/what-is-a-diode/
Looks like the wifi module, does the machine start up? What feature is missing? It's usually an integrated Bluetooth/Wireless module or some device xontroller. But it's something like that. There is a socket for it on the motherboard.
This happens more times than it should, I have seen this first hand SEVERAL times. Your hard drive has died. Plain and simple. You need to replace it and reinstall the operating system a “system restore” disk. This can be obtained from Dell for a cost. OR you can download a Windows restore disk for free using another computer. The step to do this are one the windows sight and there are several YouTube videos. Like I said, I have seen this a lot. Quite often if you have a keep ear you can HEAR the drive making an odd clicking sequence that sounds different than a normal drive in operation if you have a trained ear. Hope this helps. Sorry about your luck. It's a pain, but it's a relatively cheap fix. It's just going to cost you a few hours, and whatever was on that drive is gone forever.
Need to know the barrel size and voltage to find one. They are easy to get once you know that. Update (05/01/2016): Or Google http://www.amazon.com/UpBright%C2%AE-Mi3xPINK-Mi3x-BLK-Mi3x-SIL-Mi3x-PINK/dp/B00IJTW96M
Check the wattage of original charger. Just because it fits doesn't mean it will work correctly. For example some old iPhone usb adapters are only 5 watt. Or half an amp. Most likely you need a 2 charger for your tablet. Most larger phones even take 2amp now.