|If you simply don't care about any of the data on your system then you might be able to return the system to an as bought state. |
Each company offers some way to do that. Some make you create disks, some have an F key at boot and others may have you purchase the media. See owners manual.
If you have data then consider using the backup feature of windows 7 to a usb hard drive.
When you get the system restored, make a standard user account and only use it. Have a strong password on the admin account. Get a good security suite and apply all updates to avoid this in the future.
Hang up and live.