Hmm, 67 processes is rather high, however, 2-3% cpu usage at idle is normal.
As a test, try this...
First check your Start Menu -> Programs -> Startup to see if there is anything in there. I would say get rid of any programs that are in that Startup folder. Unless there is something you definitely need to be running when Windows starts.
Then click start, run, and type msconfig and hit enter. Go to the startup tab. Keep a memory of all the startup programs that are already unchecked. You will probably want to write them down in case. After you write down which ones are already unchecked (if any), click disable all and hit ok. It will ask you to restart which you should do then.
Once the computer restarts, try burning a disk and see if it still does the same thing. If it burns normally then, then you know you have too many programs running when Windows starts. You will then want to go back to msconfig and only enable programs that you definitely want to be running when Windows starts.
If it still has weird buffer problems, I would suspect your drive may be starting to go bad. With your specs, you shouldn't have any problems burning disks at all. I am suspecting you just have too many programs running in the background which is taking up memory.
Hope that helps!
