In Windows 98, you only need to click "Start → Programs → Accessories → System Tools → System Information", and the uptime displayed in the System Information program window is the time, accurate to seconds of Windows 98. Press F5 keys to refresh the current time.
If you check the system running time in Windows XP, click "Start → Run", enter the CMD, open the command prompt, and enter "SystemInfo" and enter the command line, you will see yourself for your own operating system. A summary, there is a line of "system start time". That is, the system is completed from the startup to the time passed. Additionally, if you are on the networked state, the connection time of the network is about equal to the system run.
