What happened to the computer before this happened? Did you try a registry cleaner tool or something? Do the shortcuts work OK and just the icons are different? Did you try to roll back to a earlier restore point?
The registry points to the icons which Windows 7 will use for "Office" documents. These icons are not the icons inside winword.exe, but some other icons, somewhere else. If, usually while "cleaning" the registry, you delete those references, you lose the icons for (the respective) "Office" documents.
I cannot remember where these icons reside, neither am I sure how to reinstate them. However, the above may help someone else to shed some more light on the issue.
Here's a slightly quicker version of the instructions.
1. Press Ctrl-Shift-Escape to get the task manager.
2. In the Processes tab, click on explorer.exe and click End Process. You'll get a confirmation dialog. Click "End Process" to confirm.
3. From the File menu (still in the task manager), choose New Task (Run...).
4. Copy/paste/enter the following command in the run box:
cmd /c del %userprofile%\AppData\Local\IconCache.db /a
5. Open the Run box again with File --> New Task (Run...). This time, enter this command:
6. All should be okay now. Open the Start Menu and confirm that your icons are fixed now.