I specd. a new computer about a year ago to run the latest editor suites. I copied the PC specification from Pinnacle Studio which I was using at the time and passed it on to my computer dealer to come up with a box that either matched or bettered the given spec. I have now updated to VideoStudio Pro X6 which performs equally as well.
One option is to run Belarc Advisor which will give you a summary of your PC bits and bobs! I run Windows 7 64bit and the spec of my PC is:-
motherboard: ASUSTeK P8H61-MX
processor: Intel Corei5-2320
Video Card: NVIDIA GeForce 210
sound_card: NVIDIA High Def Audio
Hard_Drive_Capacity: 1000 Gb
I only give this as an example.
Is processor capacity or speed a problem?
Incidentally my system is in a tower simply because it is easier to update or add components. I run two screens, one shows the video as it is being edited and the main screen has the editor controls on it. I had to add a FireWire card to the system for my Canon HV20 and I use the SD card reader for my Panasonic HC-V700.