He probably is limited to 4gb due to "32 bit" he mentioned Vista.
I believe his bottle neck isn't the charting or broker platforms, but running all the non-trading related items... CNBC, youtube, etc...
i5 - 8/16gb ram - 250gb SSD plain vanilla desktop with two inexpensive video cards should be more than sufficient to run charts, scanner and order entry platform...
(the computer doesn't care about position size or % at risk) 4 instruments and scanner isn't very intensive...
Personally, I don't see why people spec out "High End Trading Computers" when in fact they trade on General Purpose-Media Rigs...
Simpler solution: Pitch Vista, install Win7-64bit / Win10-64bit, 8 gb ram and an SSD, keep it light, "Dedicated to Trading related programs only" and surf porn on another system....
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Edit: Fresh Install of Operating system alone may cure 99% of his problems.
Suggest running
Malware-bytes, (just be sure not to install the trial version at end of install and at every update) it will prevent the nag screens to purchase.
Then run official
AdwCleaner also. I personally trust How-To Geek
The malware alone can throttle down a system...
TweakHound another trusted resource as an FYI for research