Suggest that when you get a machine set up..... before ya have a chance to bork it, run Belarc Advisor which will create an html file of all ya hardware, security status and license numbers. Then ya can d/l a OS copy, install it and activate it with the code.... at least w/ Win7
Many laptop vendors include a recover partition .... you hit a certain hotkey / key combo on boot and it restores the lappie to factory condition.
This is from an old Acer
To access the recovery partition on your Acer computer for recovery, follow the steps listed below.
1. Power on the computer
2. At the white ACER BIOS screen, hold the Alt key and press the F10 key simultaneously to start Acer eRecovery.
3. Once eRecovery has loaded, click Restore to Factory Default Settings
4. Click OK to continue
5. From here, the eRecovery process will update all the data on the C: drive and restore a fully functional factory image (approximately 10 minutes).
6. Once eRecovery has run, press OK to reboot unit
For Dell IIRC, it's F8
Just google "[insert lappie manufacturer name here] key combo to restore factory settings software"