Unused H1B expired and did not travel to US during validity periode

Hello All,

I had H1B visa and got expired on 22-Sep-2011. During my visa validity i did not travel to US due to some reasons. 

So my questions are:


1) Is there any way that I can renew my expired H1B visa. If so what is the procedure for the same.?

2) Will I come under H1B Cap Exempt?

3) Do i need new employer to file petition?

4) If at all i get visa then what would be the validity?