You may, if you wish, chose to change the default location of search index in Windows 7. It is, by default, stored at C:\ProgramData\Microsoft\Search\Data folder, which is a hidden system folder.
To do so, Open Control Panel in its ‘all items view’, and click on Indexing Options.
Next click on Advanced.
In the Index location box, click Select new.
Choose the folder where you want to store the search index file in. Click on OK.
This operation will restart Windows Search Service and indexing will take place afresh and be saved at this new location.
Want more? Check out these Windows 7 Search Indexer tips.