Support1000

Symptoms :

 - > System Freezes at the desktop
 - > Can’t open any applications

Workaround :

 - > Try in Safe Mode ( Keep tapping F8, as soon you turn on the computer to get Advance Boot Options)
 - > Try disabling Startup items and non MS Service (How to disable startup items) 
 -> Disable Hardware devices if the above step didnt work (How to disable hardware devices)
-> If the problem resolved after disabling the hardware devices you can check enabling one by one to see which hardware cause the problem

Most propably the Network adapter or Wireless adapter will be the cause for the issue.  You can try installing latest driver for your network adapter or wireless adapter.

Otherwise you may have to replace the adapter.