I have always used FL studio and I have not installed anything new, But I am wondering if I hit something by accident. Lately my CPU has just been spiking like crazy. Any time I have even just one VST instrument running I am getting CPU fluctuations. I can have one instument and a bass drum going and I am getting CPU usage of about 60 then it jumps to 80 if I tweak anything. Finally it starts sputtering and slowing to a standstill. I used to be able to run 4 vsti before it started sputtering. Anyone have an answer for me??
i wish there was a way to see what exactly is drawing all the CPU....or is there a way?

By the way I have a 3.0 single core

check the sample rate it's running at, as well as the buffer size. (Make sure you use someting like asio4all, not the "direct sound driver" if your comp doesn't have a soundcard with its own drivers."
Otherwise, if you haven't changed anything, then it may be something running in the background of your pc. Sometimes the cpu spikes are graphical issues (Switch themes lately?).

Virus scan etc too

happened to me too, try re-installing asio4all or using another asio device.

also, XP service packs kill me for a day.

What do you mean by "switch themes lately?..How do I check that?
And yes I am using ASIO4all with a Audigy soundcard....which has issues on its own. The graphics thing could be a problem as well cause I notice when I have a lot of stuff on the screen it starts sputtering. What exactly do I do about that?