What do you mean by write time ?
Does access mean any time the program was started ?
Windows direstories keep 3 timestamps for each file...
Creationtime ... when the file was first written to your disk.
LastAccessTime ... the last time the file was READ.
LastWriteTime ... the last time the file was WRITTEN to (modified)
So if you had a text file, you were working on ... CreationTime would reflect the day/time you first saved the file, LastAccessTime would reflect the last time you loaded it into your editor, LastWriteTime would tell you the last time you saved the file.
Since executable files don't get written to, you want the LastAccessTime which will tell you when it was last loaded by the system.
You can get date/time information from a few different functions in the Windows API ... FindFirstFile, FindNextFile, GetFileAttributesEx, GetFileTime etc.
These time stamps are stored in UTC format (basically the number of seconds since January 1, 1980, Grenich Mean Time) so you will need to convert them to your local time using functions such as FileTimeToLocalFileTime and FileTimeToSystemTime, etc.
Since these are a simple 64bit integer value, you can compare them easily enough to find which is older or newer... So if you were looking for files that haven't been accessed for (say) 6 months all you need to do is prepare a timestamp that is 6 months old using a function such as SystemTimeToFileTime then run through each folder with FindFirstFile and FindNextFile checking the LastAccessTimes...
Here's the scoop from MSDN ...
http://msdn.microsoft.com/en-us/library/windows/desktop/ms724290(v=vs.85).aspx