Have u heard about Event Viewer :
To open Event Viewer, follow these steps:
1. Click Start, and then click Control Panel. Click Performance and Maintenance, then click Administrative Tools, and then double-click Computer Management. Or, open the MMC containing the Event Viewer snap-in.
2. In the console tree, click Event Viewer.
The Application, Security, and System logs are displayed in the Event Viewer window.
To view the details of an event, follow these steps:
1. Click Start, and then click Control Panel. Click Performance and Maintenance, then click Administrative Tools, and then double-click Computer Management. Or, open the MMC containing the Event Viewer snap-in.
2. In the console tree, expand Event Viewer, and then click the log that contains the event that you want to view.
3. In the details pane, double-click the event that you want to view.
The Event Properties dialog box containing header information and a description of the event is displayed.
OR
If u want to monitor user access of files, folders, and printers and so on .....
Auditing User Access of Files, Folders, and Printers
1. Click Start, click Control Panel, click Performance and Maintenance, and then click Administrative Tools.
2. Double-click Local Security Policy.
3. In the left pane, double-click Local Policies to expand it.
4. In the left pane, click Audit Policy to display the individual policy settings in the right pane.
5. Double-click Audit object access.
6. To audit successful access of specified files, folders and printers, select the Success check box.
7. To audit unsuccessful access to these objects, select the Failure check box.
8. To enable auditing of both, select both check boxes.
9. Click OK.
After u enable auditing, u can specify the files, folders, and printers
1. In Windows Explorer, locate the file or folder you want to audit. To audit a printer, locate it by clicking Start, and then clicking Printers and Faxes.
2. Right-click the file, folder, or printer that you want to audit, and then click Properties.
3. Click the Security tab, and then click Advanced.
4. Click the Auditing tab, and then click Add.
5. In the Enter the object name to select box, type the name of the user or group whose access you want to audit. You can browse the computer for names by clicking Advanced, and then clicking Find Now in the Select User or Group dialog box.
6. Click OK.
7. Select the Successful or Failed check boxes for the actions you want to audit, and then click OK.
8. Click OK, and then click OK.
CAUTION: These tasks r completely for Administrative purpose. U must have the same right !
If you are going to enable auditing, make sure you audit only what you really need to audit, otherwise your logs will grow really fast, and you might find hard to process such amounts of data.