There isn't enough memory to perform this operation when opening PPT and excel.

Not enough memory to open file

 You may required to delete below registry entry.

Microsoft Excel previewer:-
 
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{00020827-0000-0000-C000-000000000046}

 
Microsoft PowerPoint previewer:-
 
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{65235197-874B-4A07-BDC5-E65EA825B718}

 
Microsoft Word previewer:-
 
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{84F66100-FF7C-4fb4-B0C0-02CD7FB668FE}