I accidentally shared my C drive – what should I be worried about? and would like to know who may have accessed my files. Is this information stored any where?
By default on Windows 7 there is no logging of network activity. It may be enabled, you can check. If it isn't enabled, then can enable it.
To enable auditing do the following:
From there you can enable auditing events.
If auditing is enabled then you can view the events in the Security Event log.
To view events:
You have little to nothing to worry about. Even if you gave people read/write permission thought the share, the file systems security takes a higher precedence and no one without appropriate permissions would be able to do anything.
In other words, they could not do anything they could not have already done before the share.