I suggest a good place to start your learning curve without having to fork big bucks out, is to glean knowledge from Howstuffworks.com-"Computer Channel". From there you can go to Hardwaresecrets.com,(On the homepage, go up to the top headers, and click on Cpu,[processor], Memory,[ram], Storage,[primarily harddrives], Video,[graphics cards, etc.) This website's 'motto' is "Uncomplicating the Complicated", and I truly believe it does. Sysopt.com, Majorgeeks.com, Tomshardware.com, PCmag.com, are websites that have up to date reviews, and archieved reviews on computers, and parts, plus info on the basics.
Directron.com, and even Ol' Newegg.com, computer parts online stores, have info on the basics also. Here, let me show you.
1.Directron.com
http://www.directron.com/byo.html
2.Newegg.com
http://www.newegg.com/Info/KnowledgeBase.aspx
Another place I like to go, Wikipedia.org I can start someone with the 'Building Block' of the computer. The Motherboard,(proper speak Mainboard) Those who've been around? Mobo.
1.Mobo: http://en.wikipedia.org/wiki/Motherboard
2.Cpu,(Processor, and DOES NOT mean a reference to a Personal Computer! Just thought I'd mention that. lol!)
http://en.wikipedia.org/wiki/Cpu
3.Graphics: http://en.wikipedia.org/wiki/Computer_graphics
Deeper into the subjects:
Pentium 4:
http://en.wikipedia.org/wiki/Pentium_4
http://en.wikipedia.org/wiki/List_of_Intel_Pentium_4_microprocessors
http://en.wikipedia.org/wiki/Special:Search?search=pentium+4&fulltext=Search
Chipsets on the mobo:
http://en.wikipedia.org/wiki/Chipset
http://en.wikipedia.org/wiki/List_of_Intel_chipsets
http://en.wikipedia.org/wiki/Comparison_of_AMD_chipsets
http://en.wikipedia.org/wiki/Special:Search?search=chipsets&fulltext=Search
Expansion cards:
http://en.wikipedia.org/wiki/Expansion_card
Expansion slots:
http://en.wikipedia.org/wiki/Industry_Standard_Architecture
http://en.wikipedia.org/wiki/Peripheral_Component_Interconnect
http://en.wikipedia.org/wiki/Accelerated_Graphics_Port
http://en.wikipedia.org/wiki/PCI_Express
Ram(Memory):
http://en.wikipedia.org/wiki/Random_access_memory
http://en.wikipedia.org/wiki/SIMM
http://en.wikipedia.org/wiki/SDRAM
http://en.wikipedia.org/wiki/DDR_SDRAM
http://en.wikipedia.org/wiki/DDR2_SDRAM
Harddrive:
http://en.wikipedia.org/wiki/Integrated_Drive_Electronics
http://en.wikipedia.org/wiki/Serial_ATA
http://en.wikipedia.org/wiki/Solid-state_drive
PSU(Power supply)
http://en.wikipedia.org/wiki/Computer_power_supply
http://en.wikipedia.org/wiki/Capacitor_plague
http://en.wikipedia.org/wiki/Quiet_PC
http://en.wikipedia.org/wiki/List_of_computer_hardware_manufacturers#Power_supplies
Form Factor for mobo's
http://en.wikipedia.org/wiki/Comparison_of_computer_form_factors
http://en.wikipedia.org/wiki/ATX
Graphics card:
http://en.wikipedia.org/wiki/Nvidia
http://en.wikipedia.org/wiki/Comparison_of_Nvidia_graphics_processing_units
http://en.wikipedia.org/wiki/ATI_Technologies
http://en.wikipedia.org/wiki/Comparison_of_ATI_graphics_processing_units
As I said the mobo is the BUILDING BLOCK of the computer system. I like to build computers,(Desktop, I just rebuild or repair laptops, and that's NO fun! lol!), that are based on the "Bang for the Buck", meaning getting your money's worth, without overspending because you gotta' keep up with the newest, fastest stuff. There's no reason to spend $1100.00 dollars on a cpu, when one $200.00 will 'smoke' sum games. Games are what's shaping computers right now. Granted,it's because the graphics are becoming more realistic, and need better cpu's, more ram memory, and better graphics cards. I just believe one should watch what they're doing, and build accordingly. My example of a starter system that will run games hard? (just mobo/cpu combo's, not peripherals, etc.)
(I lean towards Intel cpu's. That's not to say that AMD's don't do the job.)
1.http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3433136&sku=MBM-680ILT-E4500
or a 'smoker'
2.http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3478226&CatId=14
3.Think ya' gotta' have Quad Core?
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3403908&CatId=14
Ram:http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1524194&CatId=2261
Few examples of cases:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1384989&CatId=32
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2477938&CatId=32
http://www.tigerdirect.com/applications/category/category_tlc.asp?CatId=1847
http://www.directron.com/cs888uvbl.html
Psu:
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=2143209&sku=ULT33136
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3255391&CatId=106
Edit: Oh yeah,duh! When you build a computer make sure you have relieved yourself of static before starting. I build on a tabletop with plenty of room all around, but your building space may be smaller. Not on the bed, or carpet floor! Static! Be SURE to apply thermal heatsink paste on top of the cpu, before the heatsink/fan combo is put on. If it's an Intel based system, and is Pentium 4, and above, don't forget to connect the four pin connector from the power supply, to the mobo! That's the power to the cpu! Always calculate how much power in wattage that your system will need. There are free online Power Supply Wattage Calculator's. Learn about BIOS,(Basic Input/Output System), and search for articles on it, and the BIOS Setup utility. To my knowledge there are only three main BIOS makers. Award, AMI, and Phoenix. After the system is assembled the first thing you do is install the cd that came with the mobo. It's the mobo's drivers. Next is to install your OS,(operating system), disk. If it doesn't run straight from putting it in your cd/dvd-rom,(or burner),drive, go into your BIOS Setup. In Boot Order change the First Boot Device to cdrom. You can always come back here ya' know, and ask away!