I think they are two unrelated problems.

1) Did you use the preconfigured archive from the main Glidos site. If not try installing that, and set Glidos to use the Tomb.exe from there.

2) You need to install the Windows Essential Codek Pack. Also on the first use of Glidos after the installation, you should run Glidos in windowed mode so that you can deal with a dialog box that will appear: tell it to always use the pack for Glidos.

Thank you so much for your reply!! And so quick!
I apologize for not replying sooner.
Ok, I will try installing the Window Pack first.

Again, many thanks!

The FMV problem is fixed.
However, I still couldn't get the sound effects. So, back to the first question.

I did install the preconfigured archive, and tried to set glidos to start the
exe file from there(and unfinished business).
But no matter which "Game" from the Glidos menu I selected, the game either
(i) couldn't run, mentioning something anout "can't support full screen mode"
(ii) couldn't start the game, crashes every time after the FMV.

Though, again on a side note, Unfinished Business ran perfectly, but I had to
play through the whole game with still no sound effects, though I am using the
exe from the archive. Though for this one, I had to create a "New Game" on the Glidos menu instead of an preexisting one(i.e. Tomb Raider(GOA)).

With problems in fullscreen mode, try checking "Inhibit mode change (wide screen)"

Also, it is important to leave tomb.exe in the extracted archive, not copy it over your previous one.

Thank you so much for your reply.

I didn't copy any exe file and paste over other exe file tho.
Here are my current(not working) settings in Glidos:

Game Select: 123 <-- Created a new one
Adjust:
Display: OpenGL + Forced testure smoothing + Midmapping (no full screen)
CD source: CD drive: D:\ + Path to CD check file: blank
Executable: F:\Tomb Raider 1\123\TOMB.EXE
<--- This is where I installed the archive

Would this make my problem more clear?
Is 'inhibit mode change' in the setting in Glidos?

ps: Sorry if my questions are stupid, not really good with computers. : (

Your questions aren't stupid. Glidos can be a bit awkward to set up some times. The 'inhibit mode change' setting is in glidos, on the same page as the resolution, but you need to select DirectX too (also on that page).

Thank you for your patience.

Still doesn't work.
If, under DOS-Dos emulation
I pick Windows or DOSBox, nothing happens, game doesn't start
if I pick VDos32, then a warning sign appears:
Unimplemented int 21h: ax = 0900 h

Would you advise me to reinstall Glidos? Or is there some setting that I
had is incorrect?

It's looking more like the TR installation is your problem. That warning from VDos32 suggests you either have the wrong Tomb.exe or the wrong TR config. That's strange if you are using the archive because that has the correct version of the exe and the correct settings. What version of the TR CD are you using?

Reinstalling both Glidos and TR might help. At least that would give you a clean start.

Also, starting with Glidos using VDos32, and not configured to use either the audio pack or the FMV would be good to start with. If that works, the try adding each one at a time. As soon as you run into a problem report back without trying any adjustements.