I installed DCS 1.5 standalone version. problem seemed to arise after the update.   
not a great computer, but Graphics card is DX11 compatible   
=== Log opened UTC 2015-10-10 19:57:59 
00000.000 INFO    VFS: Using 'Saved Games': "C:\Users\xin7\Saved Games" 
00000.012 INFO    DCS: DCS/1.5.0.45655 (x86_64; Windows/6.2.9200) 
00000.012 INFO    DCS: CPU cores: 2, System RAM: 8072 MB 
00000.028 INFO    EDCORE: (dDispatcher)enterToState_:0 
00000.055 INFO    Dispatcher: 2015/10/10 12:57 V1508170900 
00000.075 INFO    INPUT: Device created Keyboard 
00000.430 INFO    SOUND: loaded 1051 sdefs from "sounds\sdef" 
00000.635 INFO    SOUND: XAudio2: Using device ID:'{0.0.0.00000000}.{ce2dca05-40a2-4f07-897c-ee9371c60094}' Name:'鎵0鍣?鍚瓛 (Realtek High Definition Audio)', channels: 2 
00000.635 INFO    SOUND: XAudio2: channel layout: Headphones/Stereo 
00001.037 INFO    SOUND: Using SSE FTZ/DAZ mode. 
00002.071 ERROR   VFS: Can't mount './CoreMods/WWII Units/Liveries' to '/textures//liveries/'. 
00002.083 ERROR   VFS: Can't mount './CoreMods/aircraft/C-101/Textures/Avionics.zip' to '/textures/'. 
00002.098 ERROR   VFS: Can't mount './CoreMods/aircraft/Hawk/Textures/Avionics' to '/textures/'. 
00002.121 INFO    SOUND: loaded 10 sdefs from ".\coremods\aircraft\mig-21bis\sounds\sdef" 
00002.326 INFO    DXRENDERER: Creating Resource "Unicode" of type 5 
00002.339 INFO    DX11BACKEND: TRUNK renderer init: showShaderError coreCount=1 
00002.358 INFO    DX11BACKEND: Driver Concurrent Creates - 1 
00002.358 INFO    DX11BACKEND: Driver Command Lists - 0 
00002.362 INFO    DX11BACKEND: DX11ShaderBinaries::loadShaders 
00004.919 INFO    DX11BACKEND: DX11ShaderBinaries::loadShaders finished 
00005.370 ERROR   VFS: Can't mount './Bazar/World/textures/L-39_C' to '/textures/'. 
00005.541 INFO    RENDERER: Loading metashader cache from C:\Users\xin7\Saved Games\DCS.openbeta\metashaders/ 
00005.542 INFO    RENDERER: Metashader cache: 0 (0) cached shaders out of date 
00009.401 ERROR   DX11BACKEND: rendertarget "rtDynamicCloudMap" not found 
00009.738 ERROR   DX11BACKEND: Failed to create shader resource view for /textures/raindropnormblur2.dds 
00009.738 ERROR   DX11BACKEND: VFSTextureDriver: Failed to load texture /textures/raindropnormblur2.dds 
00009.742 ERROR   DX11BACKEND: failed to create const buffer. Reason: DXGI_ERROR_DEVICE_REMOVED 
00009.745 WARNING LOG: 1 duplicate message(s) skipped. 
00009.745 ERROR   DX11BACKEND: Shader "clouds/cirrus.fx: DIRECTX11=true;" failed to create. 
00009.746 INFO    DCS: try to write dump information 
00009.811 INFO    EDCORE: # -------------- 20151010-195809 -------------- 
00009.844 INFO    EDCORE:  
00009.891 INFO    EDCORE: # C0000005 ACCESS_VIOLATION at FC227B48 00:00000000 
00009.902 ERROR   DX11BACKEND: Failed to create shader resource view for /textures/normalsemisphere2.tga 
00009.902 ERROR   DX11BACKEND: VFSTextureDriver: Failed to load texture /textures/normalsemisphere2.tga 
00009.943 INFO    EDCORE: 00000000 00000000 0000:00000000  
00010.018 INFO    EDCORE: FC227B48 0062F0C0 0000:00000000  ?GetLoadPriority@gCloudGenZW@@UEAAMXZ()+59F8 
00010.054 INFO    EDCORE: 032518C0 0062F220 0000:00000000  ?FillObjectLights@SceneManager_Implement@@AEAAXAEAVSceneContainer@@@Z()+1390 
00010.097 INFO    EDCORE: 03273223 0062F310 0000:00000000  ??0SceneManager_Implement@@QEAA@XZ()+B03 
00010.143 INFO    EDCORE: 0327DD2A 0062F350 0000:00000000  ?CreateSceneManager@smSceneManager@@SAXXZ()+2A 
00010.184 INFO    EDCORE: EEC58F45 0062F430 0000:00000000  
00010.221 INFO    EDCORE: EEC58279 0062F4B0 0000:00000000  
00010.223 INFO    EDCORE: EED1B5F1 0062FB60 0000:00000000  
00010.233 INFO    EDCORE: EED1D4B5 0062FBA0 0000:00000000  
00010.251 INFO    EDCORE: 234E13D2 0062FBD0 0000:00000000  BaseThreadInitThunk()+22 
00010.252 INFO    EDCORE: 258D5454 0062FC20 0000:00000000  RtlUserThreadStart()+34 
00012.692 INFO    EDCORE: Minidump created. 
00012.693 INFO    DCS: try to write track file Logs.rar