1> try the system restore
if he has disabled that feature
There are lesser known log files that Windows keeps, which are independent of both the Registry and individual Program logs. They are called "index.dat" files. Use the Windows Search Tool to find all occurrences of "index.dat" on your C: drive.
On XP, click Start, and Search, then For Files & Folders, and All Files & Folders, now enter "index.dat" in the Filename field. Before searching:
Limit the search to C: drive using the Look In drop-down.
Check the following options using the More Advanced Options line:
Search System Files
Search Hidden Files & Folders
Search Subfolders
Click printscreen.
Be amazed at how many "index.dat" files there are.
Minimize the Search Results window.
You need a tool to read the index.dat files. They are NOT text files.
Super WinSpy is one such reader. Or search Google for "index.dat reader". (Right-click on the Google link and select Open in New Window).
Download the software, check it for viruses (as you do for all downloads) and install it. Start the program. You can enjoy different Histories, using the button provided.
Check the computer for Usage Track eraser programs. One such program may have been used on your computer. All the following programs can erase tracks:
Tracks Eraser Pro - Registry entries plus index.dat files.
Microsoft AntiSpyware - Registry entries.
Adaware - Registry entries.
Spybot S&D - Registry entries.
One tool that can often get around the track-erasing software is NetAnalysis, by Craig Wilson of Digital Detective in the UK. One function of this computer forensic software is to search the hard disk for references that are no longer part of the index.dat file, and reconstruct additional history that cannot be found in the index.dat file. It is common to find tens of thousands of entires, and not uncommon to find hundreds of thousands.