PS3 Downloading help??????????

ok my ps3 used to download games fine now it will go up a few megabytes then just stay on a certain number.For example at the moment i am downloading the uncharted 3 beta,after keep resetting my ps3 (each time i reset my ps3 it may or may not start downloading again) it reached 740mb now it just says downloading and hasnt moved up at all. It isnt my internet as my xbox ,pc,3ds etc download things perfectly.This happen also for my black ops update it wouldnt go up in percent after about 10 time resetting it finally worked. Is there anyway to fix this?