While it's running, yes. It will not slow down you computer unless you are actively using it.
If your computer can handle all the Java and updates, you're fine. If your computer can't it might get slower.
Yes, combat arms does slow your computer down.
Yes, they can take up a lot of RAM and slow down a computer.
Any program that runs can slow your computer down, so yes.
Your computer might be slow. Slow computers cause accidents and sometimes you have to download JAVA.
will my computer kinda slowed down.
If your computer loads slow, then you need to choose the lowest qualities.
it is probably lagging because your in a populated placeor your computer is slow and have virus
No. It is the viruses you download with the songs using LimeWire that slow your computer down.
No, it will not slow down your computer and no it will not give you virus
And?
No. It is just a Java applet. While it is running, your computer may get slow, on older computers - since it is a rather large program, and due to lack of memory, mainly; this is just like your computer getting slow when running any other large program - but once you close the browser window, there will be no permanent damage on your computer.