TT_file extensions

When I click on properties - it says True Type Font.

From your original message I did not realize that the underscore character (_) was part of your file extension. I had thought you had just used it as a "space" character, since you did not place a space after the _ and before the word file.
You had said "TT_file extensions" whereas I would have said "TT_ file extensions" or even better ".TT_ file extensions"
Oh well, but that is me. Sorry. In that case...

Bob Proffitt was quite right. Microsoft typically uses the "_" (underscore) character in the third character position of a 3 character possibility for the file extensions as a signifier that the file is a compressed file. Something like .zip files are compressed, but those would have ".zip" for a filename extension. The problem with using that scheme in compressing files is that MS doesn't own the .zip scheme, and actually they wanted something that give a bit of a clue with what the file really is before you try and uncompress it (to expand it). The idea behind the EXPAND command (as Bob mentioned) is that it is simple, and the naming scheme immediately gives a clue as to what the file is.

As you said it is a True Type Font, and there are not too many programs around, at least not free ones, that create True Type Fonts.

As for whatever created it on your system, I really doubt it. It is just a font file that could be stored in it compressed format and all you need to do that is a DOS command window to reconstitute it.

Here's how.
1) Open a DOS window (perhaps by Start>Programs>Accessories>Command Prompt)
2) Use the DOS command to go to wherever that .TT_ file is.
For example, many .TT_ files are in the I386 directory, so you can type
"cd \i386"
and you will notice that your prompt will now read as "C:\I386>"
3) Assuming that the file you want to expand is called "xyz.TT_"
you then type in "expand xyz.tt_ xyz.ttf"
You should see some info like:
Expanding xyz.tt_ to xyz.ttf.
xyz.tt_: 23556 bytes expanded to 40044 bytes, 69% increase.
(Note, your numbers will be different.)

At that time your .TTF file can be dropped into the C:\Windows\Fonts directory.

There are at least two ways that I know how to do that, but you may already know them, or perhaps even more. You can also easily search for (via Google or even Microsoft's Help) for a way to use and install that .TTF font.

If you need guidance in doing that then just start up a new thread and ask. I would suggest that you first try and find out for yourself, though. That is how to learn. I would not suggest that you use this thread to ask about how to install a TTF font here, since it really is a whole 'nuther subject, and your question may get lost here.
This forum becomes more useful as a learning tool when people keep their questions directly related to the original subject line.

If I recall correctly it was from an old "PrintShop" program - it was a flyer with images for someone. I saved it when I got a new compter - not sure it ended up the way it did. Thanks again for all the help.

Sure there may be plenty of TT_ files on a program disk such as Printshop. Those are the compressed versions of True Type Fonts that are there for your use when making up various Printshop items (cards, calendars, flyers, banners, etc.). Those TrueType fonts are generally very artistic in design and can make a very nice looking font when used in those items.
When you install Printshop it will uncompress those TT_ files and make them TTF files in your Fonts directory.

TrueType fonts have the ability (like several other line-based NOT bitmap-based fonts) to scale (up and down) and not lose quality. That is a very useful ability when you go to make a banner and the characters may be several inches high, or more.

But your original ask was "I no longer have the program on my system that created this file - is there someway I can convert it to something else - so that I can open it."
That Printshop program did not CREATE the TT_ files. I hope now you understand that.

I have other files I have saved - and can open and view/print with no problem - not sure what has happened to this file. Again - Thanks

Why would you think it as strange that you can open the files your created? I'm guessing you are talking about your Printshop file, but if not then please clarify.

The files you create with Printshop are not .TT_ or .TTF extensions. Instead they may be something like .PDG, .PDL, maybe .PSW, and I'm sure others but I don't have Printshop.

This is the only files I cannot open with what is on my system.

That is unlikely. There are plenty of file types you can not directly open by just double-clicking them, and that is NOT a bad thing, either. You just are not aware of the many others. And, depending upon the setup of your system, you may not be seeing those files that you can't open. In a sense, those unregistered file types are 'invisible'.

Some files are not meant to be just opened. And your TT_ files are just one.

The "TT_" file type are compressed, they are not in a form that is directly usable. Just follow the steps that a couple of us have already mentioned in this thread, to uncompress (or expand, or re-constitute, whatever you might finally understand) and you will get a "TTF" file type, and THAT you will be able to open.

Not that that will be any more useful, since just opening it will only show you the font set look of the information inside. That is useful to know, somewhat, but the real use of the "TTF" file is to place it in your Fonts folder, so that your text using programs may use it.