Windows 7 IE problem

[rprosperi]

Before doing anything drastic (I consider switching to Chrome drastic)are you sure the date/time and time zone are all correct? If these are not set right, some sites will not let you in as the certificates can be interpreted as invalid.

Also, I would definitely reset all the certificate settings you changed back to their original settings. Changes there can lead to big problems, possibly preventing you from accessing anything.