Hello, I do have a very annoying problem with my 2 year old laptop. It does randomly freeze/crash I have waited a whole night once and it was still frozen, have happened for me while playing wow and lol and even when using browsers like ie, chrome and firefox.

Laptop spec:
Packard Bell
Windows 8.1
Intel core i7
4 gb ddr3 ram
Nvidia geforce gt 540M 1gb vram

What have I tested:
-driver update, both from Packard bell website and hardware manufacturers.
-scan for malware and windows update.
-format the pc.
-ram test (no errors)
-bought new harddisk and wireless card from Intel
-no problem in laptop temperature, often around 60C when playing.
-checked on Internet for tips (some people that I should inactive superfetch)
-gpu stresstest

It does sometimes not happen even once for a whole month but then happen more then twice in same day