samsung galaxy gt-s7500 hangs up

hi all

am a noob in here having problem of my samsung galaxy ace gt-s7500

it hangs up all the time get error message and run slow (untill i restart again works for few seconds then again hangs up ) :( : :(



error messages are ( Application adobe air (in process com.google.model.mi) is not responding

1.. the application Live wallpaper (process com.gl.live.wallpaer) has stopped unexpectedly please try again later

2........Application measure (in process com.andrioid.hardware.ext0) is not responding

thease are the error message i get and then hangs up

so i kindly request to help me out from this head ace ..

if it need to install new custom rom please let me know step by step cause am new to this installation stuff

i tried to install custom rom which i saw in this forum but while moving to recovery mode by pressing volume+ and home and powerbutton then by selecting sd card to locate the new rom but having problem there the rom is not visible there ...

hence again i request some to help me out

thanks in advance