HELP NEEDED with FF7 on PS1

Hello, i need help with some things i just brought. So with some christmas money i bought a PS1 to try and complete Final Fantasy 7 again, but it wont load up.

One lucky time i managed to get it working. But some screens took time to load, and the movie scenes were really messed up, and out of time with the sound. After the first reactor boming mission it came to the blank loading screen, where jessie is setting the bomb, but a loud and fast BEEP BEEP happened, which im guessing means the console crashed.

I havent got the game to boot since, i put it in and the console freezes on the main menu (Its trying to boot the game up, but failing to)

The disk is not badly marked or scratched although we have had FF7 since 1998. I have quickly opened the console to check for dust, and it has barely any dust inside.

The console model is SCPH-9002 and i live in the UK, so its a PAL version. I got the console off amazon for £47. I would be highly thankful for a solution for this problem. Thanks.

@likelexd: It's hard to say with an intermittent problem. If it's working fine with some games and not others, it possibly just means that the console is fine and the discs are damaged.

The black Playstation discs are quite hard to see scratches on, but I have found that even small ones can cause issues. Luckily these can sometimes be fixed. If you take the discs to a local game store or movie rental place, they maybe able to repair your discs for you. I know most GAME stores here in the UK will do this for a small cost, but some other places may do it for free if you ask. It is also worth noting that if the games have damage on the label side then they can't be repaired.

If the disc isn't damaged, it does sound like there is something wrong with the console. Do you have any other games you could try with it?

@zanelli: My father had a whole bunch of games from the 1990s, but most are lost.

I managed to find Music and Music 2000, which work smooth as butter. I found heart of darkness which works okay too, With resident evil 1 and 2 the movie scenes are very glitchy.

I have also tried Micro Machines V3 and the console crashs after i try to load up anything, like driving school or 1 player, the car drives off as i should and then says loading, but crashes.

Last game i have tried is wipEout 2097, which again, works smooth as butter. What do you reckon ?

@zanelli: Thanks for your help mate, ill probably buy a platinum edition of ff7 since the ff7 we have is the original and it means much to my father, dont think he would like it being cleaned or anything. Ill get the platinum cleaned, thanks for your help :)

@likelexd: No problem. Good luck with FF7, it's one of my personal favorites.