You should find that System Restore is turned on by default, creating restore points automatically on a regular basis, but in case you want to create a manual System Restore point, perhaps just after a virus cleanup, here’s how to do it.
There are a lot of different routes to the System Restore setup screen in Windows 7, but this is the way I use.
Click on the Start button and right click on Computer. Select Properties from the context menu and the System window will open.
Click on System Protection and the System Properties window will open, with the System Protection tab automatically selected.
Click Create and you will be asked for a name to give to this System Restore point. Try to give it a meaningful name so that if you ever have to roll back to this restore point, you will recognise the name you used.
Finally, click Create and the System Restore point will be created for you.
If you continue having problems you may want to call a computer repair technician.