Whilst I find that hard to believe, given most hardware nowadays is PnP detected (during boot, so you don't see it), but if you don't have anything attached to a USB or other bus on the machine at the moment then you may still be correct that it's not the issue. However, it is rarely seen that power causes issues, so that's why logic pointed out PnP as the easiest place to start looking.
A few questions to help us help you better - namely, when did this start (if you can remember), and with that question in mind what changed on the system before that time (patches, software updates, hardware changes, etc)? Given the very narrow nature of that svchost, the more you can provide us the more we can help pinpoint the issue.