System Restore (aka System Protection in Windows Vista, 7, 8 and 8.1) literally turns back time for your computer - it restores the system files and settings that were used at a time when your computer was still working well. It also restores your previous Windows password in case you have changed it recently - so make sure you remember your previous password!
System Restore will not touch your documents, e-mails, pictures, videos, etc. It will restore only system and program files and settings in Registry. But if you have installed a program after the time you want to restore your system to, you will still have to reinstall that program.
Never expect System Restore to remove a virus, rootkit or other malware - use free anti-virus programs and free anti-malware programs for this.
System Restore is available in Safe Mode, while booting from Windows installation DVD (in Windows Vista and later) or System Repair Disc/Recovery Drive (in Windows 7 and newer), and while running Windows normally. The only difference is that after restoring to an earlier restore point in Safe Mode or from installation DVD/Repair Disc/Recovery Drive, the action cannot be undone; if you have Windows running normally, you can undo the restoration.
In Windows 8, System Restore is off by default on most devices - Microsoft decided to rely on the new Refresh Your PC feature. You can still enable and use System Restore.
First, let's see System Restore options. Open System Properties / Basic System Information using keyboard shortcut Windows Key+Break, or right-click Computer icon on Desktop or in Start menu and select Properties.
In Windows 8, you can also use keyboard shortcut Windows Key+X to open Quick Links menu (a list of system tools) and click System. Alternatively, right-click (or tap and hold) Start "tip" on the bottom left of Desktop.
In Windows XP, click to open the System Restore tab.
In Windows Vista, 7, 8 and 8.1, click the System protection link on the left side of the window.
Windows Vista users will meet User Account Control. Click Continue.
In Windows XP, make sure that there is no check mark in the Turn off System Restore on all drives box. If there is, clear it and click Apply to re-enable System Restore.
Find Available drives. Here you have a list of hard drives or partitions available in your computer.
In Windows XP, verify that at least one drive has "Monitoring" written in the Status column.
In Windows Vista, check that at least one drive is selected.
In Windows 7, 8 and 8.1, ensure that at least one drive has "On" written in the Protection column. Please note that in Windows 8, System Restore might be off by default.
In Windows XP, 7, 8 and 8.1, you can configure how much disk space is reserved for restore points. There must be at least 1 gigabyte of free space on the disk for System Protection to work. One restore point uses around 300 megabytes. See the Free up disk space in Windows article if your device is tight on space.
Windows Vista will use up to 15% of total disk space for restore points and Microsoft provides no way of configuring it.
To adjust System Restore disk space usage in Windows XP, 7 and 8, click the drive that has Windows installed on it. Usually its letter is C: and Windows 7 has "(System)" written after it. Then click Settings or Configure.
In the Disk Space Usage section, adjust the Disk space to use (Windows XP) or Max Usage slider to suit your needs. This defines how much disk space will be reserved for restore points. In Windows 7, this also includes previous versions of files (if configured so). If you have very limited disk space, set it to at least 600 MB (megabytes) - this is the absolute minimum I would recommend. But in case you have a large hard disk with plenty of space available, you can reserve 1-5 GB (gigabytes) for System Restore and Previous Versions. Generally, 10-15% of disk space is the maximum I would use on large drives.
In Windows 7, verify that under Restore Settings the Restore system settings and previous versions of files is selected. This does not mean that System Restore will overwrite your documents, pictures, videos, e-mails or other personal data - this just enables backing up and restoring different versions of documents you have in your Documents folder and its subfolders. For example, if you accidentally delete or overwrite a document or folder, you can recover it using Previous Versions.
In Windows 8, make sure that Turn on system protection is selected in Restore Settings section.
You can see how much space is currently being used for System Protection in Current Usage row.
The Delete button (in Windows 7, 8 and 8.1 only) is meant to use with care on system drive. You should never click it if you already have problems with your Windows 7 or newer. Clicking this button will remove all system restore points and previous versions of documents and therefore makes restoring your Windows 7, 8 or 8.1 to an earlier point of time impossible.
Click OK to close settings for the selected hard drive.
Some computer vendors divide a hard disk into two partitions - one for Windows, the other for recovery. The second partition usually has a name (label) that includes the word "recovery", such as "HP_Recovery".
Also, you might have external disks or more than one hard disk in your computer and you might not want to use other drives than system drive (the one with Windows) for System Protection.
In Windows XP, click to select the drive for which you want to turn System Restore off. Then click Settings....
Enable the Turn off System Restore on this drive option and click OK.
Click Yes in the warning dialog to turn System Restore off for the selected drive.
In Windows Vista, clear the check mark for the drive you do not need for System Protection.
Click Turn System Restore Off.
In Windows 7, 8 and 8,1, click to select the non-system drive. Click Configure... button.
In Windows 7, select Turn off system protection in the Restore Settings section.
In Windows 8 and 8.1, choose Disable system protection.
Click Yes to turn off system protection for the drive.
You might want to create a restore point before installing a program you do not really know much about or before making changes to Windows or its registry.
In Windows XP, open Start menu and browse to All Programs, Accessories, System Tools. Click System Restore.
Then select Create a restore point and click Next.
In Windows Vista, 7, 8 and 8.1, click Create in System Properties window, System Protection tab
Type a description for the restore point and click Create.
Restore point creation will take some time, stand by. After the process is complete, click Close.