welcome to the forum - I'm a n00b here too, but I can say for certain that everyone here is very helpful. And it's nice for me personally to be able to jump in already too and perhaps provide some assistance.
Let me echo WCS's and gamfa's sagely advice: try a live CD. But there are
good reasons too for Virtual Machines (VM or VB).
VMs are cool since you can run more than one OS at once. I've used VMs a lot on multiple platforms, but not on Ubuntu. To try out networked configs, I often run several machines on *one* box! Yes, it's slow and gobbles up a ton of memory. Which might also be the problem you are having. Ubuntu, if I recall, is big, and a VM hogs a lot of resources - so your virtual drives might be thrashing a lot (swapping/reading/writing) because mem is low.
You do need to study the docs more as you often have to enable certain features, or load in host modules.
One of the most stable VB's I've used most is called simply "VirtualBox" from a company in Germany. I don't know if this is what's on Ubuntu - it was free last time I looked: http://www.virtualbox.org/wiki/Downloads
Sun bought them out ... hope they don't dork
Virtual Boxes can lockup or freeze. Yes, it usually is related to device drivers - the most common things you'll experience is the mouse jumping around and typing into popup text boxes turns a "hello" into "hhhhhhheeeeeeeeellllllllllllllllllllllllooooooooooooooooo".
To get to the CD, use USB, wifi, or other items can mean jumping through some rather strange VM hoops!
Howard in Florida