This answer assumes you attempted to install the update using Windows Update. If not, let me know.
First we are going to clean up some temporary files and then scan for viruses, malware, and trojans. Then we will download the SP2 file and install form your hard drive.
A. The Clean Up Part.
1. Close all programs.
2. Download CCleaner from http://www.filehippo.com/download_ccleaner
and install it.
3. Run CCleaner.
4. There will be a list with Internet Explorer, Windows Explorer, etc. Under Internet Explorer, remove the check mark next to cookies.
5. Under Advanced, place check marks next to Old Prefetch data, IIS Log Files, and Hotfix Uninstallers.
6. Click on Run Cleaner.
7. When it is done, reboot.B. The Virus Check Part
1. Download and install the Free Edition
of SuperAntiSpyware available here - http://www.superantispyware.com/download.html
2. Run the program, perform updates and perform a full scan.
3. Remove what it finds.
4. Download and install the Free Version of Malwarebytes' Anti-Malware
available here - http://www.malwarebytes.com/
5. Run the program, perform updates and perform a full scan.
6. Remove what it finds.
After performing a full scan with one and then the other and removing whatever they both find completely, uninstall these products.
REBOOTC. Clean Registry
1. Run CCleaner.
2. On the left side click on Registry.
3. On the bottom, click on the button that says Scan for Issues.
4. When it is done click on the button on the lower right that says Fix selected issues
5. Say No when asked about backing up changes.
6. Click on Fix All Selected Issues and then OK.
7. Close that Windows that pops up when it says it is done.
11, Scan for Issues again and keep doing it until no more issues are found.
REBOOTD. Download and Install
1. Download the complete SP2 for Office from here:http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=b444bf18-79ea-46c6-8a81-9db49b4ab6e5
2. Install it.
Let me know if you gget stuck on any step.