Geeetech Prusa i3 a lot problem.... and questions

[fei8820]

well... maybe is my skill or lack of knowledge.. here is something really happen to me...

the bed stick really well... no problem with pla n abs printing ..
but it only ...

sometimes it print nicely but sometimes are terrible mostly happen are not at the 1st layer but is in the middle...
sometimes the don't extrude when at the half way print.. that one really make me feel "DAMN"
sometimes it look like this


i use pla with temperature 185 bed 75...
and abs with temperature 230 bed 120...

any idea ? i really need help i almost wanna give up this Geeetech PRusa i3 printer...


Pardon my bad english hope u guys understand


please helllllpp.. i give a cup of coffee who can help ....