I think this topic has been discussed before but I can't find it when I search so sorry if I am asking a question that's redundant-- it's my first post and I'm not very computer savvy (but I can follow clear directions!) We recently started getting the " Alert! Previous Fan Failure" notice when booting our Dell 4600i series computer. I can see that there are 2 fans when I look at the back of the computer-- our cpu stands upright and the top fan runs ok. It looks like there is a fan below it-- which fan is this and should this fan be working ( stupid question,I know but I did tell you I don't know anything about computers). How serious is it if this fan isn't working and how do I fix it or get it fixed?? Thanks in advance for any help you can give.