Allotments 4 All

Every now and then after putting the machine into Sleep mode, it will not come back on. I have to turn off the machine and restart in Safe mode. then when that has booted up, I can go to Restart to get back into the full version.
Running Windows 7.
Spybot and Malawarebyte etc found no baddies in the system.
Any suggestions. Remember I am a non-technical silver surfer.
TIA.