Have you tested to see if you can access these sites in Safe Mode
This may identify any software related issues that could be the cause of this behavior.
Hosts files have been used to redirect Web site names to IP addresses, so lets verify the Hosts files.
Go to Start/ Search, and then click For Files and Folders
In the All or part of the file name
box, type hosts
In the Look in
list, click the hard disk, and then click Search
Click all the Hosts files that are found. If more than one Hosts file is found, select them all.
Press Press F2
Type a new name. For example, type Type a new name. For example, type oldhosts
, and then press Enter
Make a note of the new file name. You may have to change the name back if this does not resolve the issue.