Need help finding best parts for Vostro 200

Hey Blue,

Pretty broad question, what are your goals for the computer? Are you using it for a work station, personal use, movies/music, or gaming?

If you want to use it for gaming what game are you looking to play the most?

Totally not worth upgrading.

The only part I would suggest is low profile GTX 1030.

That can be used in newer model.

https://www.amazon.com/GIGABYTE-GeForce-GV-N1030D5-2GL-Computer-Graphics/dp/B071DY2VJR/

Getting a Precision T3500 or better as an upgrade will do fine for at least 5 years or more.

https://www.walmart.com/ip/547982643

I agree with not worth upgrading.  Its old hardware and after whatever you add you still have "old hardware".

I'm surprised it even works with only 1GB of RAM.

Foxconn g33m02  has several versions this is the same Board as Inspiron 530 and requires LOW DENSITY NON REGISTERED NON ECC ram.

@ $30 for each 2 gig dimm you are well on the way to buying a used T3500

If your Vostro 200 was shipped with a G33M02 motherboard and a 300w PSU, it will only support dual core processors. 

The processors are supported, by the Foxconn G33M02 motherboard:

Wolfdale Core 2 Duo, E8400, 3.0GHz, 6MB, 1333FSB, 65W, E0 
Wolfdale Core 2 Duo, E8500, 3.16GHz, 6MB, 1333FSB, 65W, C0
Wolfdale Core 2 Duo, E8600, 3.33GHz, 6MB, 1333FSB, 65W, E0

If your Vostro 200 MT has G45M03 motherboard and a 350w PSU, then the following Core 2 Quad CPU's are also supported,

Yorkfield Quad Core Q9400, 2.66G, 6MB, 1333FSB, R0
Yorkfield Quad Core Q9550, 2.83G, 12MB, 1333FSB, E0
Intel Core 2 Quad Q8200 (2.33 GHz, 1333 MHz FSB)
Intel Core 2 Quad Q6600 (2.4 GHz, 1066 MHz FSB)
Intel Core 2 Quad Q9300 (2.5 GHz, 1333 MHz FSB)
Intel Core 2 Quad Q9650 (3.0GHz, 1333 MHz FSB)

Prior to installing the processor, check that you have BIOS Version 1.0.16 installed, when support for new Intel CPU's was added.

Description	Version	Download
Dell Vostro Desktop 200 System BIOS, 1.0.16 Dell Vostro 200 System BIOSMore details	1.0.16
Dell Vostro Desktop 200 System BIOS, 1.0.15 Dell Vostro 200 System BIOSMore details	1.0.15
Dell Vostro Desktop 200 System BIOS, 1.0.14 Dell Vostro 200 System BIOSMore details	1.0.14
Dell Vostro Desktop 200 System BIOS, 1.0.13 Dell Vostro 200 System BIOSMore details	1.0.13
Dell Vostro Desktop 200 System BIOS, 1.0.11 Dell Vostro 200 System BIOSMore details	1.0.11
Dell Vostro Desktop 200 System BIOS, 1.0.10 Dell Vostro 200 System BIOSMore details	1.0.10
Dell Vostro Desktop 200 System BIOS, 1.0.8 Dell Vostro 200 System BIOSMore details	1.0.8
Dell Vostro Desktop 200 System BIOS, 1.0.5 Dell Vostro 200 System BIOSMore details	1.0.5
Dell Vostro Desktop 200 System BIOS, 1.0.3 Dell Vostro 200 System BIOSMore details	1.0.3
Dell Vostro Desktop 200 System BIOS, 1.0.1 Dell Vostro 200 System BIOSMore details	1.0.1

On a ten-year old system that's worth $50 on the used market, your best bet is to spend money on something newer - this is too old and out of date to be worth upgrading.