system time can not be modified reason analysis:
First, the motherboard battery (cmos) no power
Second, no modification time permissions
Third, the computer exists a virus (The purpose of such virus modification time is to make the anti-virus software not use, or cause some software to run abnormally, such as securities stock software)
Solution:
1, to determine whether the cmos battery is dead, first start the notebook After the computer enters the bios interface, then modify the time, save and exit, turn off the computer to restart, and then enter cmos to view, if the time is run according to the modification, it means that the battery is no problem, otherwise you need to replace the battery, if you replace the battery Still not, it may be a problem with the motherboard.
2, to determine whether it is a virus, some computers can be modified in windows time, but after the modification, it quickly jumps to a wrong time, this situation is a virus, if the time can be modified, but after the restart time If it is not right, then after the time is modified, start the computer and enter bios. If this time is wrong, it means that the motherboard battery is dead. If the time is right, the time will be wrong after entering windows. The description is a virus.
3, check whether there is time to modify the permissions, first figure out the windows user name of their computer, if you do not know, press ctrl + alt + del three keys to view.
1) First click Start & mdash; Run, enter secpol.msc in the Run dialog box, then press Enter;
2) In the pop-up "Local Security Policy" window, expand to "ld to" Local Policy-->User Rights Assignment" Items;
3) Then find and double-click "Change System Time" in the list on the right, a window pops up (if the operation cannot be completed, you have no administrative rights, Re-login with administrator), which lists the list of users with permissions. If you find that there is no user name, you have no permission. If you already have your username, you have permission, but if the time still cannot be modified. , the description is a virus.
4) If it is a situation without permission, increase the permission and then modify the time. If it is judged to be a virus and there is no effective anti-virus method at present, it is recommended to cancel the time modification permission of all users, and then follow the steps below!
Cancel the permission: Select the user from the list, click Delete, and then click OK.
Add permissions: Click “Add users or groups”, then click Advanced, select users from the list, confirm the selection, and then click OK to close.