Win7 fails to completely boot

[InformaticGuy]

My PC (win7 sp2 (sp2=service pack 2) boots, but after that starting windows thing it shows only black desktop and mouse with no icons, no tray, ctrl+alt+del not working, windows button not working etc. Runing Safe Mode ends with same thing, only difference is "Safe Mode" written in corners. Safe mode with cmd has one difference, cmd shows. Startup repair doesnt solves anything (says that StartUp Repair cant fix your problem), neither does Hardware check from "Repair Your PC". I am quite well educated in IT and am a programmer, but I have never enqountered this.

My specs:
8 GB RAM
Intel i3 2nd gen 3,1 GHz
NVidia GTX 750 ti
Motherboard Asus P8P67 LE
No idea which fan and power supply (I assembled it more than 5 years ago)

NO RECENT HARDWARE CHANGES. (Last change-I upgraded from Radeon HD XFXX 6850 to NVidia GTX 750 ti, Radeon drivers are UNINSTALLED, so, there are no drivers in conflict)

OS reinstallation is impossible since I do not have Win7 CD anymore (lost it 2 years ago)

 

[elbert]

Could be any number of things. You may need a new install disk to repair. Now you may have a virus. Either way a full reinstall would eliminate any viruses. You could make an anti virus boot usb. Here is a few choices for a boot usb.
http://www.digitalcitizen.life/top-free-bootable-antivirus-rescue-discs-windows-pcs

 

[InformaticGuy]

I understand. But I scaned for viruses pretty recently and, I am not sure if I can say this, but since it is legal in my country I will say this (Pirated software is not illegal here, it is only illegal to give it to others):"I recently downloaded No Man's Sky Foundation Update from skid***rel*****.com (no real address)" but I scanned before install and after install I successfully booted a couple of times. Then, once I lost power (there is this thing called "limitator", pure state scam, but can only be removed by suing state and all it does is that it shuts down all power if certain usage is reached (example:Boiler, Conditioning, TV, PC, light, washing machine at the same time make usage reach max allowed))

 

[InformaticGuy]

Could be any number of things. You may need a new install disk to repair. Now you may have a virus. Either way a full reinstall would eliminate any viruses. You could make an anti virus boot usb. Here is a few choices for a boot usb.
http://www.digitalcitizen.life/top-free-bootable-antivirus-rescue-discs-windows-pcs

Pls read my answer

 

[elbert]

I see well Just do a reinstall of your OS. This should straighten things out.