There is no virus at all with KDE. When you test any distro at any desktop
version that is going to happen. Firefox is or can be tied into the kernel of
any version of linux. Both KDE and Gnome can be very unstable. Heck when Dapper
came out. Firefox was so unstable it crash all the time. It was mainly due to
the flash player plug in's. If you DL Firefox flash blocker. You'll see crashing
was the was the pass. All so put in mind that Linux is open source. I cannot
recall paying money for it.
Linux is growing and grow with it. I been using it for 5 years and been getting
better from each up grade. When it is time to up grade to the new version. I
wait for couple of weeks and read up on the bugs.