Hi Alex ... and welcome to the forums ...
Just took a quick glance at your post, and noticed that your build version of Windows 10 is the build used in the very first public release version. That came out almost exactly a year ago. In fact, a very large updated build is being released this past week - called the "Anniversary Update" - since it celebrates the one-year anniversary of Windows 10's release.
I'm going to guess that Windows Update has either been turned off on your system, or is quite broken. You could have trouble with the configuration or health of your computer's hardware (anything from an incorrect BIOS/UEFI setting for memory/cpu speeds to a faulty or failing part, such as a bad memory module, an overheated cpu, or a faulty hard drive).... Or, you could have a malware infection disrupting things.
My recommendation would be to rule out mis-configuration & faulty hardware first, and if all is well there - proceed to fixing the software.
BIOS/UEFI settings & Diagnostics
To check the recommended settings for your computer's BIOS/UEFI refer the the user's manual for your exact model [usually available on the support website of the manufacturer]. To run diagnostics, also refer to the manual, for many newer systems have built-in hardware diagnostics that can fairly thoroughly test most of the main components - memory, hard drive, motherboard components, video, audio, etc. Computers with built-in diagnostics generally have a function key (such as F9 or F10) that you can press at system startup to show the diagnostics menus and options. You'd want to run all the tests available on as thorough settings as possible. The testing might take a few hours (especially if you have a large capacity hard drive and a large amount of system memory). But it's worth it. Should anything be amiss & your system is under warranty, you can call your vendor for free warranty replacement/repair. If your computer has no built-in diagnostics, download and create a MemTest86 bootable CD or USB (using the latest free version = 7.1, which has been updated to test the latest chipsets & memory types, as has the ability to boot in a Secure Boot/UEFI environment). Test the hard drive using diagnostics from the manufacturer of the hard drive. If you have any questions about these tests, let us know.
You do not need the "Pro" version of MemTest86, the free version will do just fine:
MemTest86 - Download now!
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Fixing the Software
Should your system prove to be configured correctly, and it's hardware passes all the diagnostic tests - you then need to decide how you want to fix the software. It can take quite a while to remove malware from an infected system. It can take quite a while to detect which of many software problems your system has, and then correct those issues. And - since your system file versions are nearly a year behind already, updating everything to the current versions might take a long time as well ... especially if you move to build 1511 before going to the latest build (1607) --- that's a lot of time.
Clean Install Quick-fix:
If you only use a few add-on programs (those that don't come with Windows), and you have installation media for these (or can download the media, and you have a license key) -- you can try backing up your personal data onto an external media (or website), erase the hard drive, and perform a fresh install of Windows 10's latest build using an ISO downloaded directly from Microsoft (either DVD or USB). You should have "digital entitlement" to Windows 10 on your computer - that entitlement was stored on Microsoft's Windows 10 Activation servers when you first got Windows 10 on the PC [either the day you bought a Windows 10 computer, or the day you upgraded to Windows 10]. The activation is specific to the hardware in your computer.
Erasing the hard drive will remove any existing malware on the drive - eliminating a fair amount of the time involved in scanning for & removing infections from your current system files. [You'll still need to scan your personal files with a good antivirus before restoring them onto your freshly installed system, though].
Windows 10 Download
To download Windows 10 build 1607 directly from Microsoft, you can visit the link below:
Windows 10 ISO
For a guide on the clean install option, plus other methods, you can read up on tips from the "MakeUseOf" folks:
How to Get the Windows 10 Anniversary Update Now
I'd advise that you use the clean-install method. It generally is a more successful method, and in your case it saves having to try upgrading over an existing build. Microsoft prefers that your computer is already running build 1511 to in-place upgrade. Yours is still on a very broken first-edition build. You would need to get build 1511 successfully installed before then upgrading to 1607.
A clean install of build 1607 would seem to be the most efficient and direct path for your computer, should the hardware prove OK.
Let us know if you have questions
