Built a budget PC

Hi to all,
I am trying to build a budget PC from salvaging a computer, I need your recommendation for parts that I should purchase to complete this system. Please note I will be running few applications at one time, mainly will be used to be connected to 32” or bigger size screen for observing & analysing charts, graphs, browsing, software, Linux operational system will be installed.

What would you recommended to use with the parts that I have :
The PC spec is as follow:
Mobo: Asus-P5KPL-CM (USED PREVIOUSLY BY Intel Pentium dual core 1.8)
Ram: 1X 2Gb ddr2(Kingston) 1x2GB ddr2 ,total :4Gb
Power supply: --------- (preferably quiet PSU)
CPU: Intel E8400 Core 2 Duo Processor - 3.00 GHz, 6MB L2 Cache, 1333MHz FSB, Socket LGA775, 45 nm
Graphic card: optional budget as follow:
1. VTX3D Radeon HD 5450 LP HDMI 1024MB DDR3
2. Sparkle GeForce 210 1024MB DDR3


Hdd: Seagate,80Gb
Sound card: SPEEDLINK SL-8866-SRD-A Stage 5.1 PCI Sound Card, Manufacturer: Speed Link
Heatsink fan : Ultra Quiet Arctic Cooling Socket 1156 775 Heatsink Fan for i3 i5 i7 Alpine 11GT
DVD.R/W: ----------------- (Option to use “Magic disk software”)

I await for your quick replies.
Many thanks
M