Hi, I think you want to connect your VA to your PC, there are 2 types of connection and you did not mention wich, well, here it is, one is MIDI, for that you may need a MIDI interface ( USB ), you need to install it before you use it, also you may need software like Cake/Sonar, Cubase, etc...the USB are the most common,you need 2 midi cables, one for in and one for out.
The other connection is audio, in case you want to record into your PC, aldo I recomend to buy am Audio capture card ( there are USB and Firewire besides PCI ), the software to record, Sound Forgue, Cool Edit, Sonar, Cubase Power Tracks Pro audio, etc. I hope it helps you.