Social security and medicare tax

[spant]

I am currently working on h1-b visa. I changed emplyer in march 2001 after 6 months of my h1-b. My employer didn't pay social security tax and medicare for first six month. Do I need to pay that, if so how.

How do i pay social security and medicare from oct, 2000 to march, 2001, if I need to ????

Thanks,