A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Try the below mentioned steps:
1. Click Start->control panel->programs->programs and features.
2. Click on Office 2007->click change.
3. Click repair->continue.
4. Open Word or Excel and check if copy paste works.
If the above step does not resolve the issue start the system in clean boot mode to check if any Non-Microsoft services are causing the problem.
http://support.microsoft.com/kb/929135
Note: Once troubleshooting is completed, ensure to start the system in Normal mode by following Step 7 in the above article
Ruchi Bisht