Stop right there!
Two issues wrong:
1) sharing your trading machine with anyone else, let alone your children.
2) an outdated V90/56kb modem.
The modem tells me you know nothing about communications and protocols. Simply put, nothing less than a V92 modem, which includes almost up to 4x faster compression than the V90 protocols.
Also, you don't have a Lan card. These used to be the only high gain broadband inputs to machines, now they are used as backup inputs.
You didn't mention your USB level. It is presummed that its at 1.0, however, you should settle for nothing less than USB 2.0. This will be your primary means of input for your realtime market data, and so forth.
Also, plan on either 2way Cable modem or DSL (ASDL, SDSL, etc.). Settle for nothing less, otherwise your fall back is on the V92 modem as input.
As far as building a machine, and you're not being computer literate, then you're as much a sucker for advertising as we all are. Thunderbird over anyother does not matter, however, the name sure makes you think you're getting somewheres.
Net, net, net -- Costco, Sam's Club, not BJ's. See what upper (highest priced) system they offer, and buy it there, inclusive of monitor, software and such. You can get DVD/RW, 1GB memory, 17" LCD / 19" LCD and a whole host of other essential goodies, along with USB 2.0 and such, and alls you do is open the box.
What you're planning on doing is not trading but wasting precious trading time building a machine, and never being sure whether the components will ever fit, work together or warranty should you start getting various "bug errors".
Face it, you need "no worries", Ha-kunna Muh-tah-ta!
what you're planning on no longer saves the money it used to, and is frought with all sorts of problems that only those in the business (technology, for technology's sake) could solve.
Cheers