|When you see "signal out of range", it generally means the screen resolution setting was changed to a resolution that's not supported by the monitor. Restart the computer, tap the F8 key, select Enable VGA Mode, & then press ENTER. Once you get into Windows, change the resolution setting to the native resolution for your monitor.|
If you're unable to see the boot screen at startup, you probably have a problem with the graphics card or possibly something else within the tower. Please post your complete system specs along with the make/model of your monitor. And it would have helped to post in the hardware forum rather than CPU/overclocking, unless you overclocked your system & that's what brought on the problem? If it did, you will need to explain more about what you did.