the one thing i noticed once, is that there's also the human error...

for example, if u have a wireless mouse, make sure u disable it (turn it off) BEFORe u put the pc to sleep... obviously...

I've had a friend not notice this shit until i mocked his ass...

also, did u run a full anti-virus/malware diagnostic on it?
could be an unwanted service running in th ebackground..