Help!! Can't connect - "can't find server"????

Sorry for the stupid Luddite-level question, but I'm just a computer layperson; anyway, I run Firefox (although I still have Explorer loaded on my Gateway laptop), and a few days ago, I was having trouble staying on the Net - I kept getting kicked off sporadically, then receiving "Can't find Server" messages, although the WiFi I was using apparently had a Very Good to Excellent signal (confirmed by the manager of the hotel I stay at twice a week).  I get a similar message when I attempt to connect via Explorer, so I guess it's a problem with my laptop.  Any suggestions out there?  I've virus-scanned, disk-cleanupped, and checked out various parameters to make sure everything is as it should be (going so far as to momentarily turn off my firewalls to see if that helped - it didn't).  So, any suggestions from the more computer-literate out there??  (that would be pretty much everyone...)

Any help is much appreciated!