Muhammad (peace & blessings be upon him) was the final Messenger to be sent and he was sent to all of mankind.
2:What do Muslim believe about OT prophets?
The ones that have been mentioned by Allaah in the Qur`aan or His Messenger Muhammad in his Sunnah are believed in as Prophets. The ones that are not mentioned we remain quiet about (we do not confirm or deny their Prophethood).
3:What do Muslims believe about Jesus?
We believe that he was a Messenger. Allaah mentions that there were 5 Messengers that had strong will (showing their high status with Allaah) and he was amongst them. The others being Abraham, Noah, Moses & Muhammad (may Allaah's peace & blessings be upon them all)
4:Are there any humans more important than ordinary people to Muslims,prophets,saints,etc?
We don't believe in saints (well maybe some sects do, but I'm not sure about that, but mainstream Muslims do not). I'm not quite sure I understand your question. After Allaah, we hold the Messengers & Prophets in high regard and then the companions and then the scholars. (Is this what you meant?)
5:What are Muslims supposed to do about people of other faiths?
Nothing. Allaah tells us to tell them, to you be your way and to us be ours. There are some Muslim countries that do not allow proselytizing but we do not proselytize to them either.
6:What are Muslims required to do,to live the way they believe God
requires?
To believe in Allaah, the Creator of the Universe, alone; to believe in the messengership of Muhammad & that he was the final messenger sent to all of mankind; to pray 5x a day; fast in the Islaamic month of Ramadhaan; pay obligatory charity every year if your wealth meets the guidelines; to make Pilgrimage to Makkah (the Ka'baah) at least once in a lifetime if you are able; to believe in the Angels; The Revelations sent; the Messengers (Prophets) sent; The Day of Judegment and Pre-Decree (fate)
7:What man made objects are sacred?
All Masjids (houses of worship)
8:What celebrations /holy days do Muslim have?
Id al-Fitr (Celebration after the fast of Ramadhaan is over) & Id al-Adhaa (Celebration after the Pilgrimage is over and it commemorates Abraham's willingness to sacrifice his son)
9

o they believe ,the God they worship was revealed to other people,with different beliefs?
Yes & no. We believe that He sent revelation to people of other faiths but the belief was always the same, to believe & worship Allaah alone. It was the people of other faiths that altered that belief and/or did not believe in all of the Messengers.
10:What is the Muslim afterlife belief?
We beleiev in Heaven & Hell
11:Is there a certain role for men,women,dress code,any medicine related issues?
Yes. Men have the role of provider & protector of his family; women have the primary role of caring for the home & children (they may work as long as it doesn't interfere with the management & proper upbringing of their children); they both must dress modestly, men covering from their navel to their knees and women covering all of the body, both except in front each other (of course) and closely related relatives. Men should be seen by men and women by women doctors if available and birth control and limiting one's children is undesirable
12:Are there different 'denominations' in Islam,and how they differ?
Yes. Thats really hard and difficult (and time consuming to explain). The basic beliefs are the same but the way those beliefs are interpreted and practised differ. That is with most sects.
Your welcome and thanks for taking the time to ask.