Very slow, buggy, touchescreen nor responding well

So this is the story:


I used the katkiss 4 rom over 1.5 year, without any problems. Now the transformer started to act very buggy.
The tablet doesn't seem to respond to 80% of what I do. Or it reacts very slow.
It feels like a computer clocked at 300 mhz. But sometimes it seems to react to all my previous orders in 1 sec, like the processor starts to work again.

What I tried to do:
-reboot
-reset
-flash katkiss 5
-flash omnirom
-flash stock asus rom
Nothing seems to help, I am now in the first installing wizard after a reset. It is almost impossible to get through it.

What else can I try to do?I think my last hope is to open up de tablet, and reconnect the cables?

Thank you for your help!!