1.Windows7 contains more applications, some more humanized operation interface settings, special effects and so on. And it takes up a lot of space. 15G is relatively small. If you delete some service components of Windows7, it may affect the normal use of the computer. I suggest you try to avoid such an operation.

If there is something wrong with your hard disk, I suggest you send it to the local service station for testing in time. If it is a product problem, the service station will solve it for you during the warranty period.

Lenovo service station information query:/Lenovo/WSI/Station/ServiceStation/default.aspx.

3. The slow startup speed of the computer is generally because you have opened many startup items or system problems. You can click Start-Run to enter msconfig, temporarily select Disable All in the startup tab, and then restart the computer to see if it works normally. If you can solve the problem of slow startup, it should be caused by the startup item of the computer. I suggest you do some optimization. If the startup speed does not improve after disabling the startup program, it may be caused by virus or system file corruption. I suggest you kill virus, or back up hard disk data and reinstall the operating system.