Mr. Fixit's PC Upgrade and Repair
PC Buying Guide
Which display is best?
The screen size and resolution may be important depending on the purpose of the PC.  The screen size is measured diagonally from the upper Left corner to
the lower right corner.  Desktop monitors range from 20 to 30 inches and laptop screens range from 11 to 17 inches.  If you plan to work with editing videos
and photos, watching movies, or need to view documents side-by-side, go for the large screen size.  For basic use, like surfing the web and emails, a small
screen size would be fine.  

Displays that uses Light Emitting Diodes (LEDs) use less energy than the standard Fluorescent back lights and still provide bright colors.  If you plan to
watch movies and shows with company,  get a display/laptop with an IPS panel to provide wider viewing angles.  Glossy finish screens give richer colors and
darker blacks, but a Matte finish has less glare when using outdoors.

Touch Screens are found on AIOs and laptops.  They make navigating the operating system more simplified, however, they are not found on mac computers.
You can Tap to select, hold and drag to move items, swipe to scroll and pinch to zoom, just as you would on a smart phone or tablet.

The Screen size also reflects the maximum resolution, measured in pixels.  The resolution is measured Horizontal x Vertical pixels.  Standard High Definition
(HD) (1366 x 768) resolution is great for Web-surfing, e-mail and basic computing tasks.  HD+ (1600 x 900) is good for casual gaming and watching DVD
movies.  Full HD (1920 x 1080) is good for watching Blu-ray movies and playing video games without losing any level of detail.  Quad-HD (QHD) (2560 x
1440) and QHD+ (3200 x 1800) have an extremely high pixel density to create crisp detail and sharp text, ideal for professional photo and graphics work as
well as high-def movies and games.   4k Ultra HD ( 4K UHD) (3840 x 2160) has four times the pixels of Full HD, creating rich colors and images for viewing
and editing incredibly lifelike images and graphics.

Aspect Ratio refers to the ratio of the width to the height of the screen.  Full screen has an aspect ratio of 4:3, also known as 1.33:1.  Widescreen has a ratio
of 16:9, also known as 2.35:1.  Widescreen is suited for graphics designs, gaming, and multi-tasking.
Optical Disc Drives?
This is not something most people think about when buying a computer.  Optical Disc Drives (ODD) are known as CD/DVD drives and you may have noticed
that many computers no longer have them, especially in Laptops and AIOs.  You may, however, still find one in a standard Desktop PC.  In order to make
computers more cost effective, compact and light weight, the Optical drive was removed because software, music, and videos can now be downloaded or
even streamed from the internet, the need for an CD/DVD drive became less warranted.  If you have programs on disc, listen to CDs or Watch DVDs, get a
PC that has an ODD.  You can also buy an External USB CD/DVD Drive to use those discs.
Ports and Connectivity?
There are several types of ports and connections a computer could have and it depends on what you need.  For Video connections HDMI will provide the best
video graphics and when connected to a TV it also provides an audio channel to the TV without the need to run a separate audio cable.  DVI is the second
best choice if your monitor doesn't have HDMI, They are not used on TVs but a DVI to HDMI adapter can be used to connect to a TV except you will need to
run audio cables since DVI doesn't support Digial Audio.  VGA is a last resort if your monitor doesn't have a HDMI or a DVI connection. VGA is the oldest of
the 3 and is often used for basic computing.

There are 3 versions of USB;  USB 2.0, USB 3.0 and USB Type C.  USB 2.0 can transfer data up to 480 Megabits per second (Mbps) and often used to
connect external drives, gaming controllers, smartphones, MP3 players and other accessories.  USB 3.0 can transfer data up to 5 Gbps with compatible
devices. USB 3.0 was designed to have a much higher speed and handle devices that required more than 1/2 ampere, which was the limit of the USB 2.0
Version.  USB 3.1 was later developed to reach speeds up to 10 Gbps.  USB Type-C is still new and you might not see this connector on the computer.  
Unlike the USB Type-A and Type-B connectors used on USB 1.1, 2.0 and 3.0, the Type-C use reversible connectors.  It can be plugged in the Host (PC) or
the Device and doesn't matter which end of the cable you use.  The USB Type-C can also be used with Type-A and Type B devices with the correct adapter.

Connection to the internet can be achieved by using either Wi-Fi or an Ethernet cable.  Wi-Fi will give the most flexibility and is often found in Laptops and
AIOs.  You may even find Wi-Fi in Standard Desktops, however, if the computer doesn't have Wi-Fi, you can use a USB Wi-Fi adapter.  Ethernet, on the other
hand, can reach higher speeds than Wi-Fi but, requires a direct connection to the modem or router and is not at all flexible.  Wi-Fi allows you have internet
access anywhere in your home without being constricted to a cable.

Multiple
audio connections are common in PCs.  Most PCs will have analog speaker output that looks like headphone jacks that connects to external powered
speakers.  Some PCs may also have an Optical SPDIF or a Digital Audio Coaxial connector.  These are used to connect the PC to Digital Surround
Receivers.  Laptops and Some AIOs have built-in Speakers and may also connect to external speakers.

Multi-Media Card readers can also be found on PCs for reading SD, CF, MMC, etc.  The most commonly used media card is the SD Flash memory card.  
Virtually all PCs will have at least a SD card reader.  Some of the Desktop PCs will have multi-card readers installed.
Operating System?
The operating System is the heart of the PC.  It manages all software and hardware, including files, memory and your connected devices.  Most importantly, it
lets you interact with your computer and your programs in a visual way.  There are 3 operating systems;  Mac OS (a.k.a. OS X),  Microsoft Windows, and
Chrome OS.

Mac OS is found on Apple computers that boasts an elegant and easy-to-use interface to complement Mac's sleek aesthetics, high build quality and
sophisticated ergonomics.  Macs have fewer issues, however, Macs are more expensive.  A 21.5" AIO iMac starts at $1,100 and a Mac mini starts at $500.  
To date, no Mac model includes touch-screen functionality.

Microsoft Windows was redesigned to take advantage of the intuitive touch-screen interface, expanding your navigation options.  It features a new task
manager, streamlined file management, a suite of built-in apps and takes advantage of cloud computing.  Windows based PCs start around $300.

Chrome OS was released in 2011 by none other, Google Inc.  Chrome OS primarily supports web applications. It has an integrated media player and file
manager. Supports Chrome Apps, which resemble native applications, as well as remote access to the desktop.  A few Android applications have been
available for the operating system since 2014.  Chromebooks, Chromebox, and Chromebase PCs are based on the Chrome OS.  These PCs are great for
those who just need a simple computer for surfing the Web, keeping up with your e-mail and social networks, and sharing your photos with friends and family.
The Chrome OS is not recommended for Advanced and Power users.  Chrome PC starts around $165.
Summary