Is it possible to customize what actions are performed when you mouse into the hot corners in Windows 8?
I'm not sure if you can change their actions, but you can disable them by editing the registry/using Skip Metro Suite (http://winaero.com/download.php?view.33).
Yes !! you can.
1st you should disable default hot corners in Windows 8. download this script and run it https://www.dropbox.com/s/fmz5ckztbzrsm95/disable-win8-hot-corners.reg
2nd install a small 3rd party app (free App), this will enable you to customize hot corners https://sites.google.com/site/programsforpeers/hotcorners