mkmusic

It appears to be a Pop Rock song from the 1990s, the lyrics are undecipherable because of the poor audio quality, but we can assume it's not English (maybe some Southeastern Asian language?).

I've spoken to my Indonesian friend, and he says that the language is probably Malay.

done

same search: https://www.watzatsong.com/en/name-that-tune/803693.html

i got some more info that may help. The animation is titled "リンセインファック.swf" (i moved it to my main pc). Translates to "Linsane F*ck" (i used deepl). after some more looking online I am very sure the characters are Lyn and Sain from a video game fire emblem (made 2003) looks exactly like them. Can't find any other information online about the this animation. I am not sure how it got on my pc back then, probably downloaded it mistakenly from a program like kazaa. I think it might have came from a website like soundclick, i feel it just aligns with the fact is was used in an old flash animation.