Not always waking from standby

My machine will, about 50% of the time, not wake from standby in a timely manner. By 'timely', I mean that after a couple of minutes, I get bored and use Remote Desktop from my laptop to wake the machine up.

When it does not wake up, the only issue is that the screen does not come on. There is a significant amount of disk activity and this is regardless of any process that were running on the machine when it went into Standby Mode. I have checked for malware and have found none.

Question: Is there some process that I can run to capture the disk activity so I can try to figure out what is going on? I do have Sysinternals Process Monitor if that would help.

Sleep