Today i did a fresh install of ubuntu 8.04, applyed all the suggested updates and then restarted my system. after that while i was browsing the web with firefox ubuntu totaly hang up with only caps lock and scroll lock leds blinking. Then i did a hard reset but the problem persist. Ubuntu hangs in random intervals no matter what i do - browse the web, download a torrent or leave system alone without doing anything it just hungs up.