Not sure on the warranty thing, never bought a "computer" as I've always made my own.
@OP
You overclocked your video card (?) and now you have no display on the monitor?
You overclocked your [insert applicable component(s) here] and now you have no display on the monitor?
What did you overclock? Does the pc POST? 1 beep? Have you tried booting into safe mode?
Unless the pc has some sort of "breakable seal" on the side panel somewhere they'll never know you opened it if all you do is reset the cmos.
How about some detail?
I got my PC a month ago. So I decided to learn overclocking and set the cpu voltage to low I think because I selected the very first setting. I can't open the PC because the seal is on side panels and it's attached to the back part of the case and says "if this seal is removed or broken it will void your warranty."
My Specs are:
1. Antec nine hundred case
2. Antec 500 watt power supply
3. Asus m3a motherboard
4. AMD Athlon x2 5600+
5. 4 modules of 1 gb 800 mhz ram-ddr2
6. 320 gb hard drive
7. nvidia geforce 8400 gs
8. Asus Lightscribe DVD-RW Drive