We've just had 5 of our laptops come into the office so that we can make some changes to their configuration. These are Windows XP Pro laptops that are joined to a Windows 2003 SBS domain. They generally don't connect to the domain as they are usually out in the field, and they use Verizon wireless cards for internet. After having the work done and going back into the field, several of them could no longer access the internet. It would bring up the following in the address bar: "about: navigationfailure"
However, we've found that if we delete their temporary files and cookies and then either reboot the computer or restart the EXPLORER service, the internet works again for a while.
These are the changes we made on the computers: Removed Local Admin rights (except on one, and that one was also affected), disabled offline files and relocated My Documents to local hard drive, encrypted My Documents and Desktop folder, installed IDRIVE.COM remote backup, and installed SPECTOR 360 remote monitoring.
Also, they can access their e-mail through outlook (using http over ssl) with no problems, they just cannot access the web on internet explorer. Scanning the systems with malwarebytes and hijackthis turned up nothing also.
Any ideas what could be happening?