In future, please post your code, not just a picture of it. 
These will not be helping:-
This:-if(val=HIGH && Old_val=LOW)should be:-if(val==HIGH && Old_val==LOW)
This:-for(i=255; i>o; i--)should be:-for(i=255; i>0; i--)
There are other problems, but I can't be bothered typing it all out from your picture. Post the actual code, (between code tags), if you want further help.
Edit: And format it properly first, with Ctrl-T.