Please help with my question

[better]

4. Honestly, you can find cables to connect your monitor to pretty much any PC.

So I wouldn't worry so much about a new tower having the same ports as your monitor. A newer PC may very likely only have HDMI and/or DisplayPort connections, and will likely have graphics capability vastly superior to what you have now. Better to get a cable to use your older monitor until you're ready to upgrade than bottleneck yourself in the future.

Also, a bit of unsolicited advice if you're planning an OS upgrade. Look into ZorinOS. (http://zorinos.com) It's a Linux distro, based on Ubuntu, the ultimate version of which costs something like $30, and comes with a ton of useful software, include CAD, 3d modelling/animation sw, office, music production software, media player, etc.

It also has the quite useful feature of having several different desktop environments, among which are ones that quite closely mimic the look and feel of either Mac or Windows, which makes the transition pretty painless, at least for the day-to-day stuff. And honestly, Linux is a lot easier to pick up, and a lot less hassle to deal with than you might expect.

And it comes with WinE, which is a Windows emulator that will allow you to run a fair number of Windows applications from within Linux. And of course you can set up a new machine to dual boot into either Linux or Windows.

Food for thought.