Really weird problem (BSOD and other errors)

[EricConnolly]

Hello guys! 
I have very weird problems with my 6 years old PC. 
So, I normally start PC and then 2 errors pop up, I clicked OK and PC freeze. (taskhost.exe & explorer.exe)

 

 

 

So I restarted PC and all was okay, but only 10 minutes and then PC freeze. 
I shutted down PC and I start it after 1 hour and another suprise. I got blue screen. 
On the other start of my PC I got "userinit.exe" error, then black screen with cursor only, then again blue screen, then again infinite freeze. 
And today I got this problem. 

 

 

Down there in the corner is written that I have illegal copy of Windows 7, but I bought Win 7 last year. 
After few restarts I have still this screen and I can move with cursor only.
I didn't install or download something before these problems so it shouldn't be a virus. Just random time, random problem.
I have backup of everything and I think it's hard disk problem, but I am not sure. 
Please help!