I´m getting sudden HUGE LAG SPIKES

Example:
I join a game, 5 sec. fine connection then suddenly a ping of 1500, 3 seconds later 610. Then 1400, then 50.

I have my Firewall and my Anti-Vir disabled. My Skype degraded to 5.1 (it has like problems with x-trap when you have 5.4, the latest version).

My PC is pretty good, except my graphics card is in repair at the moment and I got an extremly ****ty one now for a few days. I play CF on lowest settings with a framerate around 50.

If you need anymore information, please ask.
What I would LOVE to know is, what to do against this Lag.
I can´t play like that, my internet works good when I surf on teh interwebz or play other games, SO Y I NO HAVE GOOD CONNECTION WHEN PLAYING CF?? ლ(ಠ益ಠლ)
PLEASE Help!