2 Huge Problems!!! Helpppp

Hey,

I am using Limewire version 4.9 (the most recent). My OS is XP home (without SP2). 2.53 GHz intel pentium. 512MB RAM. 80GB Harddisk.

I have to problems :

- When Limewire is working in the background is slow down my computer a lot! my computer become super slow..
I have made a virus and spyware scan but nothing detected! so any help would be appreciated!

- When I am using limewire for a while my computer will not be ale to shut down! I mean that windows start to shut down but then it hangs on the screen "Windows is shutting down..." and I have to shut down it manually by pressing on the power button.
So how to fix that???
-> this problem happens only when limewire was working! even though I exit form it before pressing shut down windows!

ThankS