Hi, I cant update my os on my blackberry 8900. Help please!

[iTzGee]

I wiped my phone using bbsak but then i cant load the os on to my phone. when Ive installed the os, it opens up apploader and freezes when i click next, and sometimes after ive installed the os it opens up a desk top manager window and asks me to select my device that i want to connect but it doesn't come up with my device. Even though my phone is plugged in. only one os has worked so far. However, some of the modules are missing. so i cant download stuff.

Can some one please help me with my problem.
Thank you