I've seen behaviour like this caused by a dodgy USB device. A random process would spike and if you killed that, another one would spike in it's place. This was under windows XP. I tracked down the offending device by systematically removing things till the problem went away. Once it was removed there were no further problems. I'm guessing it was windows I/O system not coping well with the hardware problem.
Similarly, try going through any other things that might have changed around the time you started seeing the problem. The device in question also caused problems under Linux.
I've also seen exactly the opposite happen at one of my previous employers. Contractors did not count towards "headcount" but were "project expenses" and were largely immune to the layoffs that happened there.
Ha! I wish!
Leave it on for any length of time and it'll leave it's adhesive behind. You only have to look at the marks of the floor of many studios and stages where it's been used to hold cables down to know just likely it is leave marks.
Still incredibly useful stuff though...