Making an old 2000 database file work with 365

Dear All,
I have inherited an old database/program that was made back in the day of 2000'ish. I need to try make it work in todays 365 world.
Looking online I found info about changing (Long) to (LongPtr) when Long is in parenthesis and also PTRSafe

Having tried changing all the (Long)s I can find but to no avail.
File is company confidential so I cannot put it up here.

Anyone have any other suggestions? I appreciate without the file/program this is probably a big ask.......but hey, no harm asking for suggestions.

If it's access database you can open it and save it as a new format.
What you mention about PtrSafe and so means that it contains macros as well.
PtrSafe should be set only it it's 64-bit

and you only set the public or private references, you DO NOT change ALL the Longs,

Thanks for the reply. Firstly let me say that I have a VERY limited understanding of code and my knowledge goes nowhere near this problem!

As I understood it from internet searches, (Long) in parenthesis you change to LongPTR.......and those not in parenthesis you leave alone.
The declare function (which shows in red when I open the file) has to have the PtrSafe inserted so Declare Function becomes Declare PTRSafe Function

The are like 30/40 code windows that open up which I guess I will have to look thru and change

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By public or private do you mean the stuff inside ()'s where it says Public Function or Private Funtion?
Example

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What 'Long' changes do you make when it is this:

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changes

This the way to handle 64-bit compatibility:

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The LongPtr is not always necessary, just the Declare lines with a Long as result, Maybe consider Declaring Prublic

The changes are nothing to do with scope. If the variable is a pointer or window handle, it should be a LongPtr. You should really read this before mucking about with API calls, especially if you are not a coder: https://jkp-ads.com/Articles/apideclarations.asp