can i change the level of skill ?

for example i have no level to update to level 5 can i change it ?

Pserver or global dk? (you can't on global dk)

global... u sure ? have u tried ?

you can change it to lvl 200 if you want but it only visible to your eye and not to everyone. so it pretty pointless unless you wanna scam people ^^

but if i change it can i upgrade it ? and use the skill

You can't do that. You can make yourself look like your 200 with a lvl 1 character, but you can't do anything a lvl 1 player can't anyway, so that' s useless.

can i change the 20% amulet to 100% ?

You can't, I have tried that myself, sometimes only the picture changes and that it.

have u tried with winhex ?

to replace all 20% to 100%

I tried CSV, it was a LONG time ago, and there is no way that it works now. (People pay good money for that stuff, so I have no doubt that it's protected).