Hazrat Mirza Ghulam Ahmad, he was teh guy who almost single handed saved islam wasnt he? How can you believe he is the Messiah though? The Coming of the Messiah is one of the MAJOR signs of the day of judgement, he'll end all wars.... there have still been wars after Hazrat Mirza Ghulham Ahmad....
How do we know that the Messiah that is Coming is Jesus (pbuh)?
"005.117 I spake unto them only that which Thou commandedst me, (saying): Worship Allah, my Lord and your Lord. I was a witness of them while I dwelt among them, and when Thou tookest me Thou wast the Watcher over them. Thou art Witness over all things."
Two periods are mentioned here, a time when Jesus (pbuh ) dies, and a Allah (swt) looks over the people, and a time when he lives and he watches over them, Jesus (Pbuh) will return to earth and die a natural death because Allah (swt) will send him again, this is further backed up by the following verses:
"019.031 And hath made me blessed wheresoever I may be, and hath enjoined upon me prayer and almsgiving so long as I remain alive,
019.032 And (hath made me) dutiful toward her who bore me, and hath not made me arrogant, unblest.
019.033 Peace on me the day I was born, and the day I die, and the day I shall be raised alive!"
The quran tells us itself Jesus (pbuh) shall be raised alive again! and that he will also die! Also note in the verse Jesus (pbuh) says that allah had enjoined on him Zakat, this cannot happen in heaven, he can pray in heaven but he cannot give to poor people because this would mean that there are poor people in heaven, again this shows us that Jesus(pbuh) will return to earth and lead salat, and pay zakat.
Most importantly he is a sign for the day of judgement as the quran tells us in surah 43 ayat 61 "and shall be a sign for the hour" read the entire chapter and you can see that it says Jesus (pbuh) is a sign for the last days. not to mention the numerous hadith about his second advent!