Help to build gaming PC out of old HP Pavillion PC

[Symbiogen]

Hi there ,
Can i get some tips on some parts and how to install them on my old HP. I have never built a PC before so im probably gonna pick up a book or two about it. Any good cheap parts you know of would be highly appreciated and how to install them would be even be more greatly appreciated. Thanks in advance .

 

[Symbiogen]

I have the some of the specs for the PC i am trying to upgrade,

Its a HP Pavillion a6414f PC
AMD ATHLON 64 X 2 Dual Core Processor 6000+

3072 MB of system memory

360GB hard drive NVIDIA GeForce 6150 SE graphics

 

[Symbiogen]

Heres more accurate specs

Motherboard
M2N68-LA (Narra3)

Processor
Athlon 64 X2 6000
Processor upgrade information

Memory
3 GB
Memory upgrade information

Video graphics
Integrated graphics using nVidia GeForce 6150SE

Sound/Audio
Integrated Realtek ALC888S Audio

Networking
LAN: 10-Base-T

Modem: 56K WinModem

Hard drive
360 GB

CD/DVD disc drive
SuperMulti 16X DVD(+/-)R/RW 12X RAM (+/-)R DL LightScribe SATA drive

Memory Card Reader
15-in-1 multimedia card reader

Computer Case
Mid-size ATX

Power Supply
300W

I/O Ports
Front I/O ports
Back I/O ports