Open Internet Explorer. On the Tools menu, click Internet Options. On the General tab, under Temporary Internet files, click Settings. Now you can assign the amount of space you wish to reserve for your temporary internet files. If you delete them, nothing will happen than deleting them. The loading of already visited web sites may go a little bit slower, that's all.
Cheers,
PD
Another option is to click on Tools/Internet Options and click on the Advanced Tab. Scroll down till you find the Security section and find the Empty Temporary Internet Files Folder ... and click on it to put a tick (check mark) in the box and click OK.
All that will happen is that when you start IE each page you visit will be downloaded again because it is not in the Temp Internet Files folder. If you return to a page without shutting down IE it will load faster the second time because it is already there.