are you using 64-bit windows? if not, you threw the money for the extra two gigs of memory into the trash can, since it won't recognize more than 4gb.
also, neblix, that's not that bad of a processor. it's got nothing on, say, an e8400, or a mid-level i7, but it's decent enough to do less complex stuff. more than half my music was done on a 3.4ghz single-core celeron, 533mhz fsb
if you're loading this into fl studio properly and the audio's routing correctly, make sure you're fully updated. i've always found kontakt to be needlessly twitchy when you're using it as a vst, so updating hopefully will fix any complexities you're missing.