Online banking / other secure sites not working? Getting the Session state is corrupted error? The fix is likely far, far simpler than you think. 9 times out of 10 all that you need to do is to adjust your system clock to the correct time. When connecting to the banks secure systems they compare the time that your computer thinks that it is accessing it with the time that the bank thinks that it is, and if they are too far out of whack then it spits back an error because of the discrepancy. So, simply make your computers clock correct and all should be well;
If, for some reason that doesn’t work for you, then you can always reset the IE security settings to their defaults. Simply click Tools->Internet Options and click the Advanced tab. On this click Restore Defaults and then Apply.
Following that, click on the Security tab and then select the Internet icon first. Click on Default Level to reset its settings. Set the Local Intranet, Trusted Sites, and Restricted Sites all to their default levels as well.
You’re also going to want to clear the history, delete all the cookies, and erase all of the temporary internet files. All of this is under the General tab. Close IE and reopen it and then try to access your account.
If you still are not able to access the files after the previous steps, then we are quite honestly grasping at straws a bit. It is a remote possibility that something in the DNS is hosed and so you may consider repairing your DNS tables. Perhaps you are getting redirected elsewhere instead of the banks site when you try to access it courtesy of some malware messing with your hosts file or some such thing.