Scataphagos: I've only got 24.1GB on my current drive so don't need anything larger than the 120GB SSD not planning on imaging the SSD, I back up data onto a thumb drive - price data files some correspondence and that's about it, but want to keep the SSD for trading only store all the other stuff as you say on the HDD, but Q: can I get on the internet from the HDD without installing W 7 on that drive ?
The OS needs to be on the drive you boot from. So if you're using both drives in your machine, you don't need W7 on the HDD. If you plan to use the HDD separately to run the computer and without the SSD, then you will need W7 on the HDD. Of course you should backup data, but let me suggest you make a practice of periodically imaging your drive. It will save you TONS of time and work in restoring when your system gets corrupted. There is free imaging software on the net.
You can trade using Windows 98 as long as the application will install. You can have lots of ram and ssd with plenty of storage with multi-core processing. The application needs 1/50th of that to run. You need bandwidth more than you need hardware. I trade from a Galaxy Note 2 on 4G. The greater the bandwidth the higher the likelihood of early execution. Dont focus on hardware, because with all that hardware if your running DSL your S... out of luck. FAST INTERNET is the key