Turn off the Clipboard toolbar

Office 2000:

Run the Registry Editor (REGEDIT.EXE).
Expand the branches to HKEY_CURRENT_USER\ Software\ Microsoft\ Office\ 9.0\ Common\ General. If any of these branches aren’t there, just create them – one by one – by selecting New and then Key from the Edit menu.
Once you’ve highlighted the General key, select New and then DWORD Value from the Edit menu. As the name of this new key, type AcbControl.
Double-click on the new value, type 1 in the Value Data field, and click Ok when you’re done. This change should take effect immediately.
Note: supposedly, Office 2000 should automatically disable the clipboard toolbar automatically if you close said toolbar three times in succession. However, this is sortof a hassle, and doesn’t seem to work reliably. The above is really the quickest and most direct solution.

Office XP:

Open an Office application, and select Options from the Tools menu.
Choose the Edit tab and turn off the Show Paste Options buttons and Show Insert Options buttons options.
Click Ok when you’re done.