Windows 7 64-bit custom PC freezing randomly every few days

There are many reasons for this so in regards to the Kernel-Power critical error you could review,

- turning off turbo boost or dynamic cpu adjustment (BIOS settings)  
- disabling SATA3 (BIOS settings - Most devices arn't SATA3 yet)  
- disabling HPET (BIOS setting - high precision event timer)  
- disabled ATI /AMD event logger (start/Run/services.msc Find the service and disable it)  
- updated drivers (Especially the audio drivers, some older versions of the HD audio can cause crashes)  
- disabled ATI RAID Xpert (start/Run/services.msc Find the service and disable it)  
- uninstalled ATI HD audio drivers (Right Click My Computer/Properties, click on device manager and uninstall drivers for HD Audio)  
- upping the northbridge and ram voltage by 1 or 2 notches (BIOS settings)   
- disable Harddrive Sleep and Hibernate (For Desktop users: In Power Options, select High Performance, Goto Advanced options, select Hard disk, and put 0 Minutes)  


I found that I had two C-Media sound drivers in conflict. My system continually recognized them as USB drivers when I had only one USB sound driver.

Disable Harddrive Sleep and Hibernate (For Desktop users: In Power Options, select High Performance, Goto Advanced options, select Hard disk, and put 0 Minutes)

Restore to the 'old' BIOS if recently updated.

Source

check to see if you have msi command center installed, that was my issue. revo uninstall and it might fix your problem.