Processor: AMD Athlon(tm) 64 X2 Dual Core 2.50 Ghz
RAM: 2GB
OS: Windows 7
Graphics: NVIDIA Geforce 210

ASUS Z97-A Motherboard
Intel Core i5-4690K
16GB DDR3 Ram
Gigabyte GeForce GTX 770
Windows 8.1 (of course, I won't touch a windows that's older than win8 anymore)

Well done @ ohaz: You probably post MB first in this thread
And you say that win8 is good? I'm wondering to upgrade my win7 to it, or I might wait for win10 to come out..

HP
Processor:Inter(R) Pentium(R) CPU J2900 @ 2.41 GHz
(RAM): 4.00 GB
Sys. Type: 64-bit operating system, x64-based processor.
No touch or pen

Manufacturer: Toshiba
CPU: Intel Core i3 2.40 GHz
RAM: 4 GB
OS: Windows 7 32-bit
GPU: Intel HD Graphics

It's awesome. I was reluctant of keeping with the Windows 8.1 Pro that was shipped with my new PC or using Windows 7. I tried 8.1 and I'm not going back, no issues so far with gaming, and I'm pretty sure if anything happens, there's already tons of threads online on how to fix it.

I'm using Classic Shell for the good ol' 7 start menu. Windows 8.1 comes with a start button but it still uses that fugly Metro (my opinion) interface from 8, and this tool fixes that.

Motherboard: ASRock H87 Performance
GPU: ASUS Radeon R9 290 DirectCU II (4GB GDDR5) - Overclocked
RAM: 16GB DDR3 (1600Mhz)
CPU: i5 4670K (4x3.4Ghz)
SSD: Crucial MX100 128gb
HDD: Seagate ST1000DM003

Running Windows 8.1 Pro 64bit

Motherboard: ASUS P8H67-M PRO
CPU: Intel i5-2400 (4 cores @ 3GHz)
RAM: 16GB DDR3 (1333Mhz)
GPU: Palit Geforce GTX570, 1280MB
SSD: Samsung 840 SSD, 128GB (system)
HDD: 1) WD Blue 1TB, 32MB cache (2 normal partitions and RAID0 and RAID1 with...
2) WD Blue 1TB, 64MB cache.
3) external 2.5" Toshiba 2TB, 8MB cache

Windows 7 64bit

CPU: FX 6300 (3.5ghz) Oc 4.2ghz
Mobo: GA 970A - D3
GPU: GeForce GTX 760 Asus DirectCU II OC Edition
RAM: Kingston 2x4Gb HyperMemorory DDR3 1600mhz Timing(20,9,9,9[As far as I can recall[I am lazy to check my bios]])
2 HDDs. Green one 5600RPM used for storage and Black Edition 7200RPM with 4ms access time which is used for gaming and OS. Both western digital 1TB.
Power Supply: Corsair 650W

Oh and 8 Extra fans to make sure everything is running cool n quiet.

I had really bad PC, but I decided to upgrade it so now look what good PC I have!
OS: Windows 3.1
RAM: 16 MB
HDD: 4 GB
PC Model: Compaq
Video Card: Integrated

@ BountyHunter: What?!
By the way, i upgraded the windows 7 32 bit into 64 bit and i will plane to upgrade the RAM adding 4 GB additional.

See,how i take the term shit computer,on whole new level:
O.S-Win 7 ( originally Xp upgraded to 7 )
Ram - 1.50 gb
Driver-VIA/S3G Unichrome Pro Igp (Old)
Graphic card-None ( im not joking )

My pc can run games frrom 1995-2002 on high
And from 2003-2006 On very low with everything disabled

@ GeoB99: Well, actually, me PC's real stats are these:
OS: WinXP SP3 32 bit (don't laugh, I'm used to it's stability)
RAM: 2 GB
Video Card: Intel Integrated ( I have AMD and nVidia GeForce x6 1600 or something like that, but when my game pc crashed, I bought some another used pc and it's too small, I cannot mount my geforce into it, bcs proccessor is blocking the way and I don't want to took it out ye? )
Processor: Intel Pentium x4 (I have Intel Duo as(s) well, but I cannot mount some intel into old motherboard )
Fortunately, I've got some tricks and soft to power-up my pc so I can play some good games as well.

CPU: Intel Core 2 Duo E8400
GPU: GeForce GTS 450
RAM: 2x 2 GB DDR2
HDD: 80 GB
Motherboard: GA-EP45C-DS3
Power Supply: Corsair TX650W
OS: Windows 7 Ultimate Edition 64-bit

@ BountyHunter: Of course i don't laugh, Windows XP is still stable and usable today even if those guys at microsoft ended their support for this Operative System and i miss win xp.
I was thinking also to upgrade the GPU and CPU but is a bit impossible because since i use a laptop (my laptop is Toshiba C660-2C4) and some laptops can't be upgraded their GPU and CPU even my laptop can't be upgraded these things only RAM,HDD also SSD, the OS and that all i think can be upgraded so it makes sense.

@ GeoB99: About graphic card, well, I did some checking on ebay a week ago and I found there are some extension wires for PCI Express video cards. So I'm going to buy one. Now i use 80gb HDD but I also have 3 HDD I'm not using with 160, 70 and 60 GB. I have much RAM cards as well. You see, under my desk is huge pile of my old pc's thingies.

Mainboard: MSI Z87-G43
CPU: Intel Core i5-4670K @ 3.40 GHz
RAM: 8 GB G-Skill RipjawsX F3-12800CL9D-8GBXL
GPU: Sapphire Radeon HD 6850 (1 GB GDDR5)
HDD/SSD:
      1 TB Samsung Spinpoint F1 HD103UJ (HDD)
      2 TB Samsung EcoGreen F4 HD204UI (HDD)
      128 GB Crucial M4 CT128M4SSD2 (SSD, System)
      512 GB Transcend TS512GSSD370 (SSD)
OS: Win 7 64 Bit, SP1

Cpu: intel i7 4th. Gen
Gpu: amd radeon hd 7790
Ram: 16 gb
Ssd: 250gb
Hdd:1tb
External hdd: 2tb
Os: win7 ultimate 64bit & win 8.1 pro

Im currently online via phone, full stats will be added asap.

Mainboard: Gigabyte (GA-H97-HD3)
CPU: Intel® Core™ i5-4690K 3.5GHz (Quad-Core)
RAM: 16GB DDR3 RAM DIMM CL9 (1600 MHz, 1.5V)
GPU: Intel HD Graphics 4600/NVIDIA GTX 750 Ti (Palit)
PSU: VS450
Cooling: Intel Boxed Cooling
HDD:
      1 TB S-ATA 6GB/s
OS: Windows 8.1 (64-bit)
Display: BenQ XL2720Z 27" (144hz, 1ms input latency)
Mouse: Zowie FK1 Competitive Gaming Mouse
Mousepad: SteelSeries Ninjas in Pyjamas (Limited Edition)
Headphones: SteelSeries Siberia Elite (White)
Keyboard: Ducky Shine 3 (Cherry MX Blue)
Soundcard: 7.1 HD Realtek ALC887

@ DC: Hehe, DC nice to see you introduced your PC, too