Wondering????

My brothers computer worked fine in the morning, then when he started it up later it took about 10min to load to the logon screen the 5-6 minutes to logon and load the desktop. Once you are in and click on an application it takes about 3-4 min to load it up. I was wondering if the processor was failing or what??? It also runs at 100% while in windows.

Need info on what hardware you have, what version of windows, and anything that happened to the computer in between times (dropped? lightning?)