i have a mini 110 hp laptop....and my operating system is linux....
for my internet browsers is Firefox...and anytime i try to download anything from the internet it never works...example:flashplayer,skype,limewire..ect...it always ask me to save the file or open file and it always open in archive manager...and nothing never happenes after that i really need help

Save the file instead of trying to open it. Everything you mention above is usually an archive, which is why its opening in the archive manager.
After you successfully download a file, I'll bet you will be back to ask another question or two.

Okay after that i saved it and when i went to open it nothing happened it still opened in archive manager as a text and not the download itself

First of all, please don't use titles like "help", as they don't say anything about your problem and some members will not bother reading threads with titles like that. When you post a thread, you are told about using descriptive thread titles.

I don't really understand what's happening. Could you explain a bit more, please? What kinds of files are you downloading? I'm pretty sure Firefox and Skype come in tarball format (.tar.gz or .tar.bz2 for example), so it would make sense that "Archive Manager" is being used when you try and open them. Can you post a screenshot of what happens when you try to open said files?

Do you know how to run commands in a terminal? Also, which distribution are you using?