The IE/Mail hanging and the Ctrl-Alt-Del not doing what you expect (invoking Task Manager) are separate issues. I think the Vista installation is damaged, probably requiring a repair install or a system restore to a point since Thanksgiving, but before the Christmas fan failure. System Restore help
Ctrl-Alt-Del behaviour is an echo of Vista's NT lineage. Ctrl-Alt-Del was used in NT to bring up the secure logon, since that key combination could not be trapped by some rogue program pretending to be a secure system logon. (Under DOS-based Windows prior to NT, Ctrl-Alt-Del usually merely warm-booted the computer)
The Secure Logon (invoked by Ctrl-Alt-Del) on this machine is showing signs of damage. The error messages indicate that not all the dialogs can be found (i.e. files or paths may be missing).
Secure logon still exists in Vista, although it is usually set up as optional in the default policy settings, I think.
There's a fixit
One other way to change settings is:
In the start menu search box type secpol.msc and then go to Local Policies\Security Options.
Find "Interactive Logon: Do not display last user name" and change it to enabled, OK out and reboot and thereafter Ctrl-Alt-Del should bring up the logon dialog, OR set it to disabled, and the last user should be displayed for logon after standby or at startup.
Another way is the Alternate User Accounts Admin dialog:
If you just have one user and require autologon, without entering a password, in the start menu search box type control userpasswords2, and uncheck the box:
"Users must enter a user name and password to use this computer"
Under the Alternate Tab there is a check box to enable Ctrl-Alt-Del secure logon, which you want unchecked. OK out of the dialogs. Reboot.
If there is still a problem, for instance after returning from standby or after a period of inactivity that activates the screensaver, there are yet another 2 controls - right-click an empty part of the desktop, properties, screensaver, and uncheck "On resume, password protect", then click the Power button under Monitor Power, then the Advanced tab and uncheck "Prompt for password when computer resumes from standby." OK out of the dialogs. Reboot.
After all this, your machine should never prompt for passwords, and now Ctrl-Alt-Del should just activate Task Manager.