How to solve this problem: "skype cannot access to your sound card"

How to solve this problem: "skype cannot access to your sound card"

Already tried many methods such as check/uncheck the "exclusive use of the sound card", "no sound effect", etc in the sound setting. e.g.:

https://community.skype.com/t5/Windows-archive/Skype-can-t-access-my-sound-card/m-p/3937726

https://support.skype.com/en/faq/FA12097/call-quality-guide-windows-desktop?intsrc=client-_-windows-_-7.26.0.101-_-callquality

No luck.

This problem happens in real skype calls. Test in a home wifi using another end connected to the same wifi, no problem for keeping my computer and that skype end connected for more than 30mins.

 A typical screen I will have after 6-7mins of talk usually.

Need to reconnect every 6-7mins in a real web-meeting.

Sometimes it is only the problem of the speaker. 

There is once my colleague tried to plug a headphone into the laptop during a call, but not working; then he pull the headphone out and had a same error.

Computer configurations:

Operating System: Windows 7 Professional 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_ldr.160516-0600)

           Language: English (Regional Setting: English)

System Manufacturer: LENOVO

       System Model: 20BXCTO1WW

               BIOS: Phoenix BIOS SC-T v2.1

          Processor: Intel(R) Core(TM) i7-5600U CPU @ 2.60GHz (4 CPUs), ~2.6GHz

             Memory: 12288MB RAM

Available OS Memory: 11984MB RAM

          Page File: 5112MB used, 18854MB available

Sound Devices

-------------

            Description: Speaker/HP (Realtek High Definition Audio)

 Default Sound Playback: Yes

 Default Voice Playback: Yes

            Hardware ID: HDAUDIO\FUNC_01&VEN_10EC&DEV_029.....

        Manufacturer ID: 1

             Product ID: 100

                   Type: WDM

            Driver Name: RTKVHD64.sys

         Driver Version: 6.00.0001.7383 (English)

      Driver Attributes: Final Retail

            WHQL Logo'd: Yes

          Date and Size: 11/11/2014 20:45:28, 4275288 bytes

            Other Files: 

        Driver Provider: Realtek Semiconductor Corp.

         HW Accel Level: Basic

              Cap Flags: 0xF1F

    Min/Max Sample Rate: 100, 200000

Static/Strm HW Mix Bufs: 1, 0

 Static/Strm HW 3D Bufs: 0, 0

              HW Memory: 0

       Voice Management: No

 EAX(tm) 2.0 Listen/Src: No, No

   I3DL2(tm) Listen/Src: No, No

Sensaura(tm) ZoomFX(tm): No