What laptop is it?
If you can download the full manual from the manufacturer, using another computer, you can find the correct buttons for bios setup.
Open the bios setup, by holding down the button(s) shown in the manufacturer manual, during the starting of the computer.
set the DVD drive to boot first (read and follow the directions, in the bios, to save the change and exit).
The windows 7 install disk must be in the drive, restart the computer...
select "upgrade" This will NOT erase your personal files.
This will NOT erase your programs.
This re-installs the drivers and sets the operating system back to default, allow the computer to do this, and don't interrupt the re-installation.
After the computer re-installs and reboots, it should work normally again.
If the computer won't work normally again, this is an indication of a hardware failure..however, your personal files, photos, etc... can still be recovered.
at that point, a tech is going to open it , recover files, and replace what failed...
It is possible for a virus to disable re-installation by upgrade....but it is still possible to recover your files.
The "upgrade" re-installation is the surest way to eliminate a corruption of the operating system, without erasing your own files. It also will upgrade the version of OS, etc..., if it has an established internet connection. I would recommend you connect wire internet, not wireless, however...
You will know for sure that the thing has been cleansed, with the factory brushes....and it has the best chance of recovery and success.