If so, check your power settings in windows and in the BIOS also turn on some of the wakeup functions like for keyboard and/or mouse.
I have a new and powerful PC. I bought it about 3 months ago and from about three weeks ago while playing Second Life the PC was completely frozen. I have been able to restart it only manually. I checked the CPU and its behavior is very efficient, never exceeds 45 degrees even working with 2 or 3 programs simultaneously, I made a memory test and all seems well, finally I followed the behavior of the GPU and playing Second Life with high graphics settings and the program "Fraps" opened simultaneously can reach 62 degrees. (The GPU is NOT overclocked). Now, sometimes I go to sleep and when I'm back, the PC is frozen again. So it make me think that maybe the problem is not related necessarily to any program.
I have an ASUS Sabertooth motherboard FX990, GPU: AMD Radeon R9 200, PSU: Coolermaster 700W, CPU: AMD FX-9590-8 Core 4.7 GHz with liquid cooling, RAM: 16 GB. Case: Thermaltake Level 10. Windows 7 Home Premium.