my safari and firefox won't start downloading automatically

[yuenzhi]

my mac book is experiencing some problems lately, how can i put this right, let just say that my safari and firefox wouldnt start download some links automatically. for examples some megaupload links and some website like this one redsn0w.com. when u click on 'UNSUPPORTED TETHERED REDSN0W - REDSN0W LITE' firefox or safari should start the download automatically, put mine wouldnt. i have to right click and choose 'save file as' to download the file. i have a friend, she's using the same spec macbook as me and she also uses the same wifi as me, when i gave her the megaupload link which i can't download and also the website redsn0w.com, she didnt have any problem downloading them. i apologize if my explanation is not clear. if u need details u can ask me. thank you in advance