Are you trying to see what your kids have been up to?
In that case you can try browsing to the Temporary internet files folder located at C:\Documents and Settings\Default User\Local Settings\Temporary Internet Files and see if you can see any pages or images viewed, However once again if the files have been deleted you will have no luck.
To be honest the only way to consistently be able to see what someone has been up to on the internet including browsing, Instant Messaging, file downloads, emails etc is to use a program like spector pro or eblaster from spectorsoft http://www.spectorsoft.com/
These are programs that remain hidden on a machine that only you can view that will allow you to look back at any time to see what someone has been up to.
Let us know if you have any more questions.
If the history and the temp files have been deleted then there is nowhere you can go.
You could try using a data recovery program to undelete the files such as OnTrack http://www.ontrackdatarecovery.com/ however you will not be able to recover the history in the same easy to read format, You will get a series of files that contain everything that has been deleted from the machine so if you dont know what you are looking for you may have some trouble finding whatever it is you are searching for.
If you can let us know exactly what you are trying to do we may be able to advise you better.
If the save history option was turned on in windows messenger then a copy of the IM messages and logs should be in the C:/my documents\my received files \username \ history folder.
If there is nothing in the folder then again you will need to use an undelete software to recover the logs.
If the emails were in Hotmail then it means a web browser was used to send/receive the messages so if temporary internet files were deleted your only option would again be to attempt an undelete, Or if you suspect his kind of thing is going to happen again you can try the Spectorsoft software I suggested earlier.
To be entirely honest if you wish to find out what is hapening your only real option is to use a monitoring software which will capture all activity as even if the files were not deleted you would not be able to see copies of messages as place like hotmail have security in place so you could tell someone was on hotmail but you would never see what they read or wrote unless you had access to law enforcement forensic software.
Let me know if you have any other questions or need more info.