Random connection / signal issues with Wireless in new vostro

Hi all, i believe this is where it should be vs vostro forum..

anyhow, Im a bit noobish when it comes to tech stuff but here is my situation. At work when i turn on my laptop (spec'd below) usually i will catch our wifi signal and connect (i sit about 20 feet away from our wireless router) but every now and then my signal just drops? if i go to my connections page and click the refresh connections icon it will pull up 5 networks we will say but my network is not there, if i refresh again it will pull up 1, again it will find 9 or so, and when it does find my network it will connect to it but not the internet and if i refresh again it will lose all but 2 networks?? and so on and so forth, if i let it sit randomly later it will have foudn my network and reconnected. Is this common? I was told it might have to do with interferance from everything around me? but it seems so random some days it will work well with not hitch others it will almost fail all day...

dont know if this has any relevance but with lan connections i have to have the ether net cable plugged into my laptop before i turn it on otherwise it will not connect to the internet it may connect to the network but not the internet, where as if it is plugged in to the computer before i turn it on im good to go in most cases, unless i am going from one lan to a diffent at say a differnet location, when i plug into a new lan it doesnt work the first time i usually have to reboot to get it to connect.

thanks in advance!

-j