Viruses can disturb us in anyway! they will even disable System Restore. I had such an experience and I found a solution for it.
- Make sure you are logged in as System Administrator
- Open Run Dialoge Box from Start > Run…
- Type gpedit.msc and press Enter
- Group Policy window will open. Expand the tree as shown in the image below
- Look at the right pane, you will see an option saying Turn off System Restore
- Duble Click to open it and select the Disabled option from the Setting tab