How to create, save and retrieve DWORD value to registry using mfc

It would be good to know what is not working.

First, read the documentation of the used functions.

Then check the return value of each function call and report the error code (at least in debug builds to be detected during development):

LONG err = reg.Create(m_hKeyParent,m_myKey);
if (ERROR_SUCCESS != err)
{
    // Report error here
}

I have not tested the code but assume that this fails with an invalid handle error. See CRegKey::Create[^]. The hKeyParent parameter muste be a handle of an open key.

But there is no need to create the key. Just use Open() because it will create the key if it does note exist yet:

// Open key (creates it if it does not exist yet)
LONG err = reg.Open(HKEY_CURRENT_USER, L"Software\\MyRegDemo");
if (ERROR_SUCCESS != err)
{
    // Report error here
}
else
{
    reg.Close();
}

When reading a boolean value stored in a DWORD, a zero value should be interpreted as FALSE and non-zero as TRUE. It is common to write a '1' for TRUE but some write also the value with all bits set.

So you should always check for zero / non-zero when reading such values:

DWORD dvalue = 0; // Default
// ...
m_chkbox1.SetCheck(dvalue != 0);

Note that I have initialised dvalue in the above example. While this should be always done, it is important here when your program is executed the first time because the value does not exist yet (it is created when leaving your program).