More recently introduced terms such as 'annually laminated' are synonymous with varve. Of the many rhythmites in the geological record, varves are one of the most important and illuminating in studies of past climate change. Varves are amongst the smallest-scale events recognised in stratigraphy.
PCs are designed to shut down automatically when heat endangers the hardware. To find out if this is your problem, download and install Speedfan. It's small and free. Although Speedfan's basic job is controlling the speed of your PC's fans (you probably guessed that by the name), it also provides the CPU temperature.
How to properly shut down or restart Windows XP. To shut down your computer in Windows XP click on the Start button () to open the Windows XP Start Menu as shown below: Once the Start Menu is open, please click on the red power button as indicated by the blue arrow in the picture above. This will open up the power options dialog box.