my iphone dont start, my iphone dont start

Could you please try to do the following:

1. Charge the phone

2. Press together Home and On buttons for several seconds and see what happens.

For me this solution don't work.

The iphone restart before that start screen appears.

The apple start appeas by 10-15 seconds and restart.

The worse problem is that in iTunes this iphone don't appear to me restart the iphone with the manufacter conditions.

I try do it in others computers with iTunes and my experience is the same.

Help!