Black Screen - Can't Run Explorer.exe With Task Manager

Hi guys

I have been Googling the answer to this for the last day and nothing has seemed to work.

Basically, my laptop was working fine until this morning, when I restarted it. After the Welcome screen, just a back screen with the mouse. CTRL ALT DEL and all that still work normally. I can run programs with Task Manager but can't run explorer.exe. It comes up in the Processes for about 10 sec then disappears. I believe this is the cause for the black screen. I have tried downloading a clean explorer.exe and replace the explorer.exe in C:\Windows\. My computer didn't allow it as it said I need administrator's permission but of course I'm the administrator so I don't know what that's about.
I tried rebooting in Safe Mode and that works fine, still I can't replace the explorer.exe in the C:\Windows\ because I don't have administrative permission. I tried to change it in the Security tab in Properties, couldn't either.
I have also tried to Update Driver Software of the Display Adapters, checked the Shell value in the registry and made sure it was explorer.exe, used the Black Screen Fix from Pevx, used HitmanPro and Windows Malicious Software Removal Tool to scan and delete malwares. I even did a scf /scannow, checked driver C for error (which took 3hrs!!!), let Windows StartUp Repairs sort things out, attempted a System Restore but failed. It said the antivirus (Sophos) was preventing the system restore so I temporarily disabled its on access scanning but still can't restore to an earlier point (11/01). The only recent program changes as listed in the system restore is Google+ Auto BackUp which came when Picasa updated 3 days ago and a newer version of Facebook Video Calling which I never used. I'm now running a scan with Sophos, not too promising.
So yeah, I have tried everything. I think there's only three options now:

1. Somehow replace the explorer.exe in C:\Windows\ with this new fresh explorer.exe I downloaded, with an administrator's permission
2. Attempt another System Restore but I'm sure nothing will happen again, already tried three times.
3. Reinstalling Windows 7 Home Premium. This will be a real pain.

So PLEASE HELP ME!!! I have coursework to hand in on Monday and this laptop is not letting me doing anything. THANK YOU!!!

Thank you guys I'll give it a try :)

ICit2lol said:

Yep VietDam and mate if you have to using the ones I posted including the MBAM on a stick and run it from there in safe mode.

Thank you ICit2lol and Neverhavemoney. I just did a full system scan with Malwarebytes recommended by both of you (is that what you mean by MBMA) but I installed it onto the computer so maybe I'll redo it this time from a stick, because the last system scan found 112 malwares, I removed all of them and yet the problem still persists. If this also fail, do you think I should jump straight to the Bootable Antivirus Rescue CD Kaspersky recommended by ICit2lol?

ICit2lol said:

Well I would also do the Superantispyware and the ADWCleaner too VietDam and then the Kaspersky bootable disk that would at least give a little more depth to the scans.
Yes Malwarebytes is often referred to as MBAM.

Just out of interest what security are you running in real time? ie Norton , AVG Avast etc etc?

If you e running tow at the same time it is generally a no no as they may in reality be conflicting with one another.

Some system specs would be good too .
System Info - See Your System Specs
if you cannot run this then some info on CPU RAM hard drive etc etc

Thank you. I sort of attempted the bootable Kaspersky and failed miserably, eventhough I enabled and disabled all sorts in the BIOS, change the boot device priority for USB HDD and CD as I was booting from each of them. Failed. Windows just kept taking over.
I'll now run Superantispyware and ADWCleaner.

I'm using Sophos as it was offered for free by the university, but I thought I have disabled its on-access scanning so should there still be conflicts?

My laptop is Samsung Notebook NP300E5C. It's 6GB RAM, 500GB Hard drive but that's about all I can recall since I don't have the manual with me here, nor does the computer let me check the properties of My Computer without explorer.exe running. I can reboot into Safe mode though and get this info now.

Following my last comment, so some specs of my laptop are:
Samsung Notebook Series 3 NP300E5C
RAM 6GB Hard Drive 500GB
System type 64 bit
Processor Intel(R) Core(TM) i3-2370M CPU @ 2.40GHz 2.39 GHz

Just so you know, someone suggested it might be a corrupted user account, so I created a new one, but the same thing happened. Just that this one has a basic blue screen, instead of black, with the basic white cursor.

VietDam said:

...I even did a scf /scannow,...

If that scan came back clean - then explorer.exe is not corrupted.

Boot to the safe mode...
...copy your files off while you can
...uninstall Sophos
...try regular boot

If that fails...
...boot to the safe mode
...try a clean boot:
Troubleshoot Application Conflicts by Performing a Clean Startup