Some tech questions and what not

[KimJongLulz]

So, of course this is my first post here hurrah.

I was wondering what exactly do they mean by low end computers can run it...I might just be the defintion of low end....

OS: Vista 64bit SP1 (I cant get SP2...at all...)
Mobo: MSI MS-7309 (K9N6PGM2-V)
CPU: Athlon II X2 250 (3.01ghz Dual Core)
Video Card/GPU/Whatever: 9800gt 1gb
RAM: DDR2 4gb
PSU: 750w

NOW thats not exactly the best computer in the world...matter of fact it was a pre built computer...the only thing I changed was the PSU and Video Card (They tried to call a 9600gt a "gaming computer card")...yeah. NOW I am wondering will my computer run PS2 "Decently", im not looking to completely destroy the graphics just enough so its playable (comfortably playable)

I am also trying to figure what to upgrade. I am looking to get a Phenom II X4 945, its AM3 and is 95w (mostly the only quad core I feel comfortable putting into my mobo...that would even work.)...then again I am VERY MUCH READY TO UPGRADE TO WINDOWS 7....problem is I have been through hell and back with MS support to try and get SP2 installed but no avail...I cant even repair my OS with a "back up installer" they taught me to make... I am scared to spend 100 bucks on Window 7 only to learn I cant even upgrade to it. (which I find HIGHLY disputable.) AND then there is the GPU...I don't know the 9800gt has been faithful so far, of course I have to use beta drivers from like 2011 because most if not all the drivers on 2012 crash NVDDLKM.sys or whatever and of course gives me a green youtube video. I might get a upgrade some day, once again I am concerned about the mobo and bottlenecking. RAM is good...its the max the mobo uses DDR2 and 4 gb.

Budget is very limited so...yeah. One thing at a time is good enough for me.