One of the family Apple notebooks (a Macbook) was having some issues waking up from sleep periodically. It was also having issues when the lid was closed the fan would constantly spin as though the machine was overheating. I took the machine into the only Apple store I trust (the main tech there is pretty solid, although he still doesn’t use Terminal). The fix was pretty simple:

1. Open up Terminal (Google it if you’ve never done it)
2. Type in ‘cd /var/vm’
3. Type in ‘rm sleepimage’

It looks like this:

$ cd /var/vm
$ rm sleepimage

This should fix any issues with sleeping and waking up. The root cause is that if you move the machine to fast, have any static electricity and shock the machine, or otherwise jostle it too much when it is going into sleep mode (just after you close the lid), the sleep image will become corrupt and you’ll start having issues.