1, the motherboard BISO battery is dead. Replace it. The battery is not big. Lithium batteries are generally sold in computer cities. You can ask the boss how to replace them. Restarting the computer after entering or not entering the desktop may be a system failure or a hardware problem. You can try reinstalling the system first. If there are still some phenomena, it is a hardware problem. Find someone to fix it.

2. After reinstalling the system, the problem of system startup failure should be solved.

3. CPU10% or more is normal. There are always some programs that start automatically at startup, which will consume some system resources. Optimize after reinstalling the system. This is a software problem, it doesn't matter.

4. It has been answered for you at 1.

5, reinstall the system, and then download some optimization software, such as optimization master, 360, Master Lu (formerly Z weapon) often do system cleaning. If the original partition of drive C is too small, partition it again before reinstalling the system. Generally, the space of disk C is recommended to be more than 8G.