D-link card HELP?

Ok heres a really weird problem..Ive had a post going in the hardware section for a few days now about my computer. Ive been having some really weird 20-40% cpu spikes and sometimes higher, and my cpu runs at a constant 20% usage even though the idle says 99%...I thought this was a software error till today. Ive checked for viruses and all that, But today when my wireless D-link card wasnt getting a good connection to the router I moved the antena and I got a better connection. Well my Cpu Spikes also Quite completely and my computer ran with no spikes. Now I know its not the connection to the router thats doing it, because ive had very good before and its still spiked. Its something about moving that antena that does it, but why? and how do I fix it?