increase upload size

i am using godaddy windows hosting delux plan, i have total 5 domains added in my hosting account by added in a separate folder, my all sites are runing under wordpress. my problem is when i upload a file larger then 2mb from my any wordpress websites admin panel, that says http error after 99% complete, i have tried to all method for increasing my upload size. but could not successful, what the hell are going wrong, i have modified my php5.ini file, theme function, web configuration,and recycle app.pool in IIS7. what is the problem, i cant find any solution or any satisfied answer or article on internet. recently i have used a plugin for increasing upload sized, but its also could”nt increase upload size,when i call to godaddy support, he says there are a code or script problem in my website, but here is my all wordpress website have this problem,i am very frustrated. someone can help me please please please,