Ok, so maybe a weird question: I've got two windows PCs on the same network. One of them is, when not in use, almost always in sleep mode. The other PC is only turned on every now and then.

I've narrowed down the issue to the fact that when this second PC is started, the first PC seems to always wake up from sleep. I've not enabled any wake on LAN features on either computer, and as such I'm a bit lost on where to go next. Any ideas?