"this file could not be found" - Windows Mail cant open attached file

After installing Internet Explorer 8 on my Vista system, I am experiencing a lot of problems. Many of them are cleaned up but there is a one problem in particular which I havent been able to resolve. So here's the problem, usually, when I receive a word document file attached in an email and when I try to open the same by double clicking on it then Windows I get a prompt to open the doc file and then Windows 2007 opens up, but as soon as the file tries to open, I get an error message saying that "This file could not be found." Similar problem happens when I try to open a PDF file, the adobe acrobat reader opens and gives an error that "There was an error opening this document. This file cannot be found." Therefore I dont think that it is a file association problem. So, can anyone tell me what kind of a problem is this?

I agree to you that it is not a problem of file association or any kind of antivirus protection issue. This problem is actually related to Windows Vista security meatures and the changes done by the Internet Explorer 8 which you have installed. This issue has been reported by many users now and still now microsoft hasnt come up with a solution for same. The only workaround till date is to uninstall Internet Explorer 8 and things will be back to normal.

Well, we will have to wait until microsoft releases a hotfix for this issue and in the meanwhile you can try to uninstall Internet Explorer 8 by following the below suggestions:

1. Close all programs.
2. Click Start and then click Control Panel.
3. Under Programs, Click Uninstall a Program.
4. In the Task pane, click View installed updates.
5. In the list of installed updates, double-click Windows Internet Explorer 8.
6. In the Uninstall an update dialog box, click Yes.
   Note: If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
7. Follow the instructions to uninstall Internet Explorer 8.
8. After the program is removed, restart your computer.