Posted 25 October 2012 - 08:39 PM
Antivirus usually isn't a problem. It's not needed, but it doesn't bother anything. If you have limited resources, that changes. I wouldn't install it.
Specs for your machine would help. However, the usual things that help can still help: a little more disk drive space; more RAM; a light desktop; a faster hard drive.
If you can't do the first two or last one (you could do one of them by dumping Winders and giving all its space to linux, but that's your decision to make and live with), you can still do something with the third one. Kubuntu isn't the lightest distro with the lightest desktop. You can get pretty much the same thing by using Xubuntu, which is lighter with XFCE than KDE on Kubuntu. Or you could use Lubuntu, which is even lighter, sporting the LXDE desktop.
It's even possible to install one of the other desktops and use that without ever losing Kubuntu. However, sometimes the desktops don't work quite as well as using the distros that are set up with them in the first place. Plus you have the problem of using up even more space unless you uninstalled KDE after you're satisfied with the new desktop.
Barring that, turn off all of the effects you can (fading windows, wobbly windows, shading around the edges, window animations, etc) if you can't part with Kubuntu.
By the way, I was in a similar situation to you back in 1997 (laptop with 780M drive, 128M RAM, dual-boot Windows and linux, plus it had all of the linux install files on the same drive in the Windows partition because it didn't have a CD drive). After a few months of struggling and dual-booting, I wiped the drive, installed linux (Redhat at the time) and never again owned a machine with Windows on it that wasn't wiped right away. And I haven't missed a thing.