First, make sure your server’s configuration is right:
right click on my computer and choose Properties. Choose Advanced tab, then click Settings.
Choose the memory dump type(which controls how much data is dumped). A Kernel memory dump may be too large for the free OSR service. So you may need to choose the small memory dump option. Then choose the path to save the MEMORY.DMP file.
Then open the http://www.osronline.com/page.cfm?name=Analyze, and upload the file for analyze.
If you can not find the problem via this way, try reliability monitor:http://frankfu.click/microsoft/windows-fundamental/windows-reliability-monitor.html