BSOD putting to sleep - DM_Log_collector, SF-Diagnostics fail

After several years of solid service my machine is beginning to show errors. Most consistent is a BSOD every time I try to put it to sleep (S3 hybrid). Reading a crash dump I see that NTOSKRNL.EXE is the last to run.

Unfortunately DM_Log_Collector fails. Attempting to run it produces" "Windows cannot access the specified device path or file. You may not have the appropriate permissions to access the item" even when run as Administrator.

Also unfortunately the only SF-Diagnostic Tool (run as Administrator) module that seems to "work" is MSINFO32, which collects all the information but then after the progress bar has completed and the progress box has disappeared, it produces a "You need permission to perform this action" error. When cancel is selected it produces the error message "Unhandled exception has occurred in your application." etc. and "Could not complete operation on some files and directories" etc. All other modules produce similar error messages early in their functioning.

I have scanned for virus. I'm up-to-date be with Windows Update. I tried to reinstall my video drivers and it seemed to help temporarily but then the problem returned.

Any advice would be greatly appreciated.

One additional note. I've tried to get the Win 7 SDK package but my download aborts with the following: "A problem occurred while installing Windows SDK components. Installation of the Microsoft Windows SDK for Windows 7 product reported the following error: Please refer to samples\setup\HTML\Configdetails.htm document for further information." I have no idea where that file is or even if it would help.