Problem with device drivers  

i recently put Windows 7 Build 7000 on my Acer 5100 laptop, and i love it. the only problem i am having out of it is i can't get any of my USB's to work on it. i have tried nearly everything that i can think of to try to get them to work, and have succeeded twice, only to be let down later. the first time i got them working, they worked great for about three days. the second time, though, only three hours. If anyone can help me out with this problem i would greatly appreciate it.

ive tried going to the acer site and downloading the drivers, but it still didnt work.