Microsoft Office sku011.cab
When trying to open Excel / Word, it prompts for CD and ask for the file SKU011.cab
Regedit (start menu -> run -> type regedit)
Expand HKEY_LOCAL_MACHINE -> Software -> Microsoft -> Office -> 11.0 -> Delivery
There should be only 1 directory under Delivery, which is your DownloadCode (mine was 90000409-6000-11D3-8CFE-0150048383C9). Select that directory. On the right side of the screen, right-click on CDCache. Change the value to 0.