A President can serve up to 10 years in office, but may only be elected to serve two terms. If a President dies in office with less than two years left in his term his successor may finish that term and still be eligible to serve two full terms in his own right.
Presidents can only serve up to 8 years in office. Other than that Mrwizard is correct.
If you'er talking about the USA presidential terms will be 2 terms. If he she or it were elected for second term then yes the could do a second term
8 years
10 years
They can serve 4 years