Well seeing that you have a dell more than likely the BIOS is locked.
But with a PC like mine for example you could go into the BIOS and do it. Raise FSB, voltages etc. etc. Or some programs will do it in the GUI, for example NVIDIA NTUNE, or ASUS AIBooster.
I would not recommend it if you don't have a good CPU cooler or good airflow in your case.
|Intel Q6600@3.0ghz|¿|ASUS MAXIMUS FORMULA|¿|2GiG Corsair XM2 DDR2 800|¿|EvGa 8800GTS|¿|36gig Western Digital Raptor 10,000 rpm|¿|Ultra X2 connect 550W modular psu|¿|Thermaltake Tsunami Case|Vista 64bit|
Windows has Blue screens, Mac has grey screens, and CF has White screens!!
2004 Mazda RX-8 GT Titanium Grey, Greddy Exhaust, AEM cold air intake
--objects in rearview get smaller with each shift--