Have you checked the battery connection inside of the device to see if it has come loose?

Is the diopter set correctly? On the lower right corner of the viewfinder, if you take the eyecup off, there should be a small dial. Turn it until the focus points are in proper focus.

It could be a bad case of resource allocation. Go to the task manager by using the keyboard, then leave the computer to sit for 10 minutes. Come back and record the approximate CPU load. Continuously move the mouse for 30 seconds, then see what the CPU load is. If it's the same, then it could be a larger underlying issue. If it jumps a significant amount, see what the program is that is causing such usage, and see what you can do about that program.

There are several things that you can do: 1. Start by making sure that all of the lenses are clean on the Kinect sensor bar. Use a soft microfibre cloth and use a polishing motion. On the IR sensor (the one that doesn't look like a normal camera), you may want to use a small amount of glass cleaner, but just use a little bit of water on the cloth to clean. There should barely be water, just enough to loosen dirt. 2. If the console itself is dusty, it may be thermal throttling to protect itself. Use the Xbox One Fan Replacement guide to remove the dust. Don't remove the heatsink unless you have additional thermal paste to reapply, and you know how to reapply the goop. Use a can of air to blow out the dust in a static-free environment. NEVER use a vacuum, as this can cause static buildup and zap your stuff. (Static electricity is bad for electronics). What is thermal throttling? Modern processors create massive amounts of heat, especially when they're under load. Computers, like consoles, have coolers on...

Have you reseated the display connector? Reseat it, then do a NVRAM reset (hold down Cmd+Opt+P+R on startup), and if that doesn't fix it, try an SMC reset.

Isopropyl alcohol is safe to use on most PCBs. Don't get it on any mechanical parts though, like optical or hard drives, or fans. Use 70-99% isopropyl alcohol and use a swab to dab it on, then if debris needs to be cleaned off, use a soft cloth. Once the debris is clear, dab on a little bit of alcohol over the surfaces in question, then let it evaporate completely. Don't get anhydrous alcohol, as pure chemicals can be dangerous and finicky to work with.

Where exactly did you get the battery from? If it's not up to spec, or it can't communicate with the phone, it won't work. Some batteries CLAIM to be compatible, but contain the wrong number of cells, the wrong type of cells, or the improper wiring. Additionally, cheap batteries may not have the proper safety certification, posing a serious fire or explosion risk. iFixit's iPhone 5 Battery has all the pertinent safety information, as well as validation for power specs.

I would start by using the Xbox One Hard Drive Replacement guide. Skip steps 22 and 23, then follow the steps in reverse order to put your Xbox back together.

Get an Ethernet cable and connect your computer directly to the router. Open the device manager, then expand the section for network adapters. Find the network adapter that has 802.11, wireless NIC and/or WLAN. Right click on the adapter, then Update Driver Software. Search automatically for driver software. If it can't find it, right click, then click Properties. Go to the Details tab, then Hardware IDs. Do a web search for the shortest string, making sure to add any special symbols (&@^*). Find what the hardware's "dumb name" is (as opposed to the display or "smart" name). Find the manufacturer's website (Qualcomm, Realtek, etc) and get the latest driver.

It sounds like a connectivity issue or speed issue. Are there any thick or dense (brick or steel backed) walls or any large chunks of metal (a refrigerator) or anything that creates interference (computer towers) close to your router or to the Echo? What's your internet speed, and what kind of load do you normally have on your network? If you notice that when streaming HD video, Echo has issues, then you may have a slow internet connection.