I’m wondering if I might have a bad (or weak) power supply (I have an Antec case with a standard 350w p/s). Sometimes when I power up my PC, all of my USB devices are not recognized (e.g. - their ICONs don’t show properly in the windoze systray)… Also, some other non-USB items that appear in systray are occasionally missing (most notably my Creative Volume Control). In both instances a re-boot (or sometimes several re-boots) clear up the problem.
Also, If it’s not power supply related, what might it be. This has been going on for quite a while now, although lately it seems to be getting worse.