Computer ISSUE Either with the internet security - firewall or any startup or the browser.
Start - Run - www.google.com
My computer address bar - www.google.com
try on a different browser if available
Check in SAFE MODE WITH NETWORKING
  NOT Able to go online   Able to go online
 
Browser issue antivirus/ firewall
Try system restore if possible Try system restore if possible
Internet Properties - restore defaults/ reset web settings cleanboot - msconfig - restart - check in normal mode
if IE7 then uninstall - restart / download and install IE7 check for the corresponding service that is interfering with the connection. Possibly it would be a firewall service of an internet security.
Reinstall IE thru add/remoce windows components
uninstall/reinstall internet security / disable service from msconfig / turn off firewall feature.
Try any one accordingly
Download a diff browser - thru ftp or try thru my computer- incase if already on dellconnect - push the setup file for mozilla directly. start - run sfc /scannow (cust must have the os cd - takes 20-40 mins)
Repair on the 3rd screen / PC RESTORE / OSRI.