Lost 5 Gb of disk space ?

After a few beers a friend offered to backup my Windows 7 system in case my sytem crashed. I told him to go ahead and next day found that my free space had dropped from 215 Gb to 210 Gb and that I was unable to create a restore point. I asked what he had done, but he could not remember what programme he had use to do the backup. I know this is a very vague question, but any suggestions as to what I can do to find where this backup might be stored so that I can delete it and recover the 5Gb. Thanks in advance.

Open windows explorer. Click on the drive (example C: ) so you are searching from the root Go to the search bar and click it. Select Date Modified and select the date from the calendar (or click Yesterday). It should show you all files touched that day.

Nice tip TM, thanks.

You can also check if he just used the built in backup program in windows itself. Navigate to your Control Panel and if you see the Category called "System and Security" you select "Back up your computer", If windows backup was used the main screen will show a backup size and a link called "Manage Space". From this link you can delete the backup entirely and if your computer was set up with a schedule, it will be listed on the main backup screen and can be disabled from here.