BSOD right after login error 0x7f caused by ntoskrnl.exe+7efc0

Your crash dumps are not showing any finite probable cause. In such a situation, it is better to enable Driver Verifier to monitor the drivers.
Driver Verifier - Enable and Disable
Run Driver Verifier for 24 hours or the occurrence of the next crash, whichever is earlier.

   Information

Why Driver Verifier:
It puts a stress on the drivers, ans so it makes the unstable drivers crash. Hopefully the driver that crashes is recorded in the memory dump.

How Can we know that DV is enabled:
It will make the system bit of slow, laggy.

   Warning

Before enabling DV, make it sure that you have earlier System restore points made in your computer. You can check it easily by using CCleaner looking at Tools > System Restore.

If there is no points, make a System Restore Point manually before enabling DV.

   Tip

• If you fail to get on the Desktop because of DV, Boot into Advanced Boot Options > Safe mode. Disable DV there. Now boot normally again, and try following the instruction of enabling DV again.
• If you cannot boot in Safe mode too, do a System Restore to a point you made earlier.

Let us know the results, with the subsequent crash dumps, if any.

Do some general USB related troubleshootings ....
For the port, first, uninstall and reinstall the USB ports drivers.

1. Right click on Computer icon > manage. It will open the computer management window.
2. Click on "Device Manager" in the left pane, it will list all installed devices up.
3. Expand "USB Serial Bus Controllers" by clicking on the triangle in front of it.
4. Click on one item to select, then right click and uninstall.
5. Do the same for all.
6. Restart the computer.
7. At restart, windows will auto configure the appropriate drivers.

And, Disable USB Selective Suspense too.
USB Selective Suspend - Turn On or Off


For the devices, first, detach all the USB devices other than the keyboard and mouse.
Then, Update the drivers for them all, including the keyboard and mouse, if any third party drivers are installed for them.

You do it first, ok :)

At least it will not harm anything, but some SUB related errors are recoverable by doing this.

Daemon Tools, Alcohol 120% and Power Archiver Pro uses SCSI Pass Through Direct (SPTD), which is a well known BSOD causer. Uninstall Daemon Tools at first. Then download SPTD standalone installer from Disk-Tools.com, and execute the downloaded file as guided below :

• Double click to open it.
• Click this button only:
• 
• If it is grayed out, as in the picture, there is no more SPTD in your system, and you just close the window.

Free up the startup.

1. Click on the Start button
2. Type “msconfig (without quotes), click the resulting link. It will open the System Configuration window.
3. Select the “Startup” tab.
4. Deselect all items other than the antivirus.
5. Apply > OK
6. Accept the restart.

I guess you have two antivirus programs installed.

Code:

Start Menu\Programs\Norton 

c:\program files\microsoft security client\msseces.exe

Uninstall Norton and all Symentec products using Norton Removal tool. Use Microsoft Security Essentials as your antivirus with windows inbuilt firewall, and free MBAM as the on demand scanner.

Download and install those, and then run full system scans with both of them, one by one.

Update your network drivers.

• Realtek PCIe GBE Family Controller: Realtek
• Intel(R) 82579V Gigabit Network Connection: Intel Download Center
• Qualcomm Atheros AR9002WB-1NG Wireless Network Adapter: ATHEROS Wireless drivers for Windows
• NETGEAR WNDA3100v2 N600 Wireless Dual Band USB Adapter

Apply the latest version of nVidia display driver.
You may download it directly, from our forum link Latest NVIDIA ForceWare Video Drivers Windows 7; or you may opt for the Option 2 of Drivers- Download NVIDIA Drivers for “Automatically find drivers for my NVIDIA products” (it requires java installed).


Let us know the results.