1>reboot your PC
then start again pressing DEL/F12/ ,,,,,,,,to get into BIOS .....
last option "restore default"
this way u can default your BIOS settings .....
2>Start ur PC pressing F8 .......lots of list comes...
last option "last known good configuration " hit enter ......
3>open folder option press "restore default "
4>restore at earlier time .....
5>..........
open all windows settings ......page n press default ......
thus u can default your PC ......but not make as much default as your PC was .......