My iPhone 2G with the firmware version 3.1.3 is having some problems with the touchscreen. The uptop buttons are sometimes touched without any contact or the first one in the recently called list is called again. However when in i cannot get into wifi section while the same area is working in springboard. As every area of the screen is responsible in some apps, I don't think it is a hardware problem. If someone can offer some insight I would really appreciate it.

By the way I know iPhone 2G is old but I don't want to change something other than iPhone and don't have adequate resources to get a new one.