[MrObvious]

A hard reset if you aren't familiar is a process to clear out the phone so that all the memory is wiped on the phone (not the storage card) and your phone is fresh like the day you first got it or flashed the ROM on it. Just push the two soft keys (the little white dot ones) and push the soft reset and you'll see the dialog.

Make sure you back up. I would start with the program PPCPimBackup.