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00005.542 INFO RENDERER: Metashader cache: 0 (0) cached shaders out of date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