At first I was going to say "That's a bug I've never seen before"
But... a gt240??
I've my doubts that is capable of properly running the game... Its extremely old, and isn't even gaming oriented technology (x50's are entry levels in their respective generation, 60/70s would be what most 'gamers' would consider 'pretty much required' and 80(and potentially some special models here and there) are top tier, 40s are just high-tier non-gaming oriented, and the 2xx was.. quite some time ago. I wonder if it was even at the point where HD was becoming more mainstream....
Anywho. Your PC specs are... darn near brick imo.. and its quite likely that something in the game just doesn't run on your hardware properly. - From what I hear, The next version should bring back Foliage low = no foliage, which will help graphical load.. but... I don't think it'll help THAT much...
You should consider getting pretty much any graphics card you can to replace your current one
You could pick up a pretty much any x60 or x70 GTX and it would make a world of difference, and not all of them, particular some of the older ones, are that expensive
https://www.logicalincrements.com/
You can also use this site to see some of the price-point choices for the previous.... "well known?" tech
More than likely, apart from the RAM amount, everything in the absolute bottom tier (at the top of the chart), is better than what you have.. whether or not that will actually be enough to properly run games like MLBS.. that.. I do not know. but almost assuredly its better than what you have.
your Athlon is bordering a decade old tech, the Athlon 200GE will almost assuredly outperform it, even though it may not necessarily be to the point of properly running MLBS and other games
of course the r3 2200 and 2400 would be better choices, but its not always simple to just say "yeah go out and start spending money, no no, more than that, higher." and actually expect to see something of it.
If you can get one of those three, and it work just fine with your motherboard, That would be best, then you would simply take your gt240 out, and rely on the vega integrated graphics
If your motherboard can't properly support, or even interface, with the newer chip, that's less ideal, as that means far more reassembly and price.. and/or those that don't like to take apart and rebuild their computer... buying a new computer altogether.