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You can put the computer in clean boot and then try to download.
Try performing clean boot and then see if the issue still persists or not. To help troubleshoot error messages and other issues, you can start Windows Vista by using a minimal set of drivers and startup programs. This kind of startup is known as a
"clean boot." A clean boot helps eliminate software conflicts. Follow the steps below: 1. Log on to the computer by using an account that has administrator rights. 2. Click Start, type msconfig.exe in the Start Search box, and then press ENTER to start the System Configuration Utility. 3. If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
4. On the General tab, click Selective Startup, and then click to clear the Load startup items check box. (The Use Original Boot.ini check box is unavailable.) 5. On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all. 6. Click OK, and then click Restart. If you are able to boot without any issues, please follow the later steps after clean boot that is steps 1 in the below article: http://support.microsoft.com/kb/929135
Next try download and run System Update Readiness Tool.
This article describes the System Update Readiness Tool for Windows Vista-based computers. Microsoft released the System Update Readiness Tool to resolve certain conditions that could cause installing updates and other software not to work. You do
not have to manually run this tool.
If nothing works, you can manually download and install 2007 Microsoft Office Suite Service Pack 2.
If nothing works, please visit the link below that will offer the support you have requested for, as the issue you have posted is related to MS Office and would be better suited in the Office Online community.