What would hapen if....?

A couple of different scenarios, but they mostly involve Harry being dead. Depending on which, Voldemort can win or die simultaneously.
So, all in all, it would be a very. bad. thing. if Severus had been a loyal DE.

If Tom Riddle had died while at Hogwarts?

If Harry was in Slytherin, he would regret being one. This said, he would be friends with low key Slytherins. I doubt he would be friends with Malfoy because he chose sides with Ron before the sorting ceremony. Also, if Harry was reeeaaallly in Slytherin, he would have died in his second year, and Voldomorte would regain all his powers. Why? because Harry would probably never developed a relationship with anyone and he would feel like a loner since everyone would call him the "true heir of Slytherin." Such a tragic ending if this were the case.

Would would happen if Harry killed Peter Pettigrew in the third book while going back in time (during the time turner)?

sum1 else wud have helped voldy cum bac 2 power!!! nd probably cedric wud not have been killed!!!

What would hapen if....snape married lily???

Then we'd probably have a Harry Snape....

WWHI Bellatrix abandoned evil and became good after Voldemort's absence?

She probably would help the order of teh phoenix kill all of the death eaters throughout the world, since she probably knows all of the hidden locations.

WWHI: Harry and Voldomorte both died in the chamber of secrets?

Voldemort would stll had his horkruxes..
Ron, Lockhart and Ginny would be still stuck in the chamber..
Nevile would continue Harry's job, and we'd have NL and prisoner of St. Mungo..
the trio would be: Nevile, Hermione and Dean..
we would have only three books, since Nevil wouldn't be able to figure out how time-turner works

wwhi Voldemort knew about Deathly hallows from begining?

From the beginning when? When he was in school or when he killed the Potters?

Probably any knowledge of the hallows would suffice...

WWHIF: Ron and Harry never resolved their friendship after Ron found out Harry was one of the Tri-wizard champions?

The story just wouldnt be the same w/out the trio. Especailly the last book. They need each other!

WWHI Harry and Cho stayed together?