I was going through a Wordpad Doc. looking for something else where I store useful URLs and came across the following for resolving File Association problems.
I've had it a while so not sure if it will also serve Win 10, but you could create a restore point first or use Windows Repair program to do a registry back up.
I'm not sure why you need to run Notepad as an admin though.
Re: this file does not have a program associated with it for performing this act
Your problem relates to file associations. If you go to all programs accessories and right click on notepad select "run as administrator" it should open.
Copy all below into notepad then in notepad menu select "File" then "save as" in the box make sure "all files" is selected(drop down) and call it Exe.reg save to desktop. Locate the file and double click it, agree to add to registry. Restart computer. (this returns to defaults and is perfectly safe)
Windows Registry Editor Version 5.00
[-HKEY_CLASSES_ROOT\.exe]
[HKEY_CLASSES_ROOT\.exe]
@="exefile"
"Content Type"="application/x-msdownload"
[HKEY_CLASSES_ROOT\.exe\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"
[HKEY_CLASSES_ROOT\exefile]
@="Application"
"EditFlags"=hex:38,07,00,00
"FriendlyTypeName"=hex(2):40,00,25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,\
00,6f,00,6f,00,74,00,25,00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,\
32,00,5c,00,73,00,68,00,65,00,6c,00,6c,00,33,00,32,00,2e,00,64,00,6c,00,6c,\
00,2c,00,2d,00,31,00,30,00,31,00,35,00,36,00,00,00
[HKEY_CLASSES_ROOT\exefile\DefaultIcon]
@="%1"
[HKEY_CLASSES_ROOT\exefile\shell]
[HKEY_CLASSES_ROOT\exefile\shell\open]
"EditFlags"=hex:00,00,00,00
[HKEY_CLASSES_ROOT\exefile\shell\open\command]
@="\"%1\" %*"
"IsolatedCommand"="\"%1\" %*"
[HKEY_CLASSES_ROOT\exefile\shell\runas]
"HasLUAShield"=""
[HKEY_CLASSES_ROOT\exefile\shell\runas\command]
@="\"%1\" %*"
"IsolatedCommand"="\"%1\" %*"
[HKEY_CLASSES_ROOT\exefile\shell\runasuser]
@="@shell32.dll,-50944"
"Extended"=""
"SuppressionPolicyEx"="{F211AA05-D4DF-4370-A2A0-9F19C09756A7}"
[HKEY_CLASSES_ROOT\exefile\shell\runasuser\command]
"DelegateExecute"="{ea72d00e-4960-42fa-ba92-7792a7944c1d}"
[HKEY_CLASSES_ROOT\exefile\shellex]
[HKEY_CLASSES_ROOT\exefile\shellex\ContextMenuHandlers]
@="Compatibility"
[HKEY_CLASSES_ROOT\exefile\shellex\ContextMenuHandlers\Compatibility]
@="{1d27f844-3a1f-4410-85ac-14651078412d}"
[HKEY_CLASSES_ROOT\exefile\shellex\DropHandler]
@="{86C86720-42A0-1069-A2E8-08002B30309D}"
[-HKEY_CLASSES_ROOT\SystemFileAssociations\.exe]
[HKEY_CLASSES_ROOT\SystemFileAssociations\.exe]
"FullDetails"="prop:System.PropGroup.Description;System.FileDescription;System.ItemTypeText;System.FileVersion;System.Software.ProductName;System.Software.ProductVersion;System.Copyright;*System.Category;*System.Comment;System.Size;System.DateModified;System.Language;*System.Trademarks;*System.OriginalFileName"
"InfoTip"="prop:System.FileDescription;System.Company;System.FileVersion;System.DateCreated;System.Size"
"TileInfo"="prop:System.FileDescription;System.Company;System.FileVersion;System.DateCreated;System.Size"
[-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.exe]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.exe]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.exe\OpenWithList]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.exe\OpenWithProgids]
"exefile"=hex(0):
[-HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.exe]
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.exe]
@="exefile"
"Content Type"="application/x-msdownload"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.exe\PersistentHandler]
@="{098f2470-bae0-11cd-b579-08002b30bfeb}"