If someone could help me.
I have Epox KTA3L and tbredB 1800+ i I cant find out how to OC proc. with raising voltage. Is it possible on that board to do so?

I assume you mean the Epox 8KTA3L right? I had a regular 8KTA3 and I overclocked a duron cpu from 750 to 1000 stable. Go into the BIOS and in the upper right corner there should be an area called voltages/??????, go in there and you can change the FSB, multiplier, and voltages assuming you have unlocked the processor unless your XP doesn't need to be unlocked, I dunno since i haven't tried to overclock mine, yet..... Be careful and up things slowly.

theres the problem! theres big diference btw OC those two boards. I've seen + model in manual and it is a bit diferent. As i remember it has that blue switch box to manage voltage. Mine dont. Like it wasnt meant to be OC with voltage. Or i cant find out how to do it.
In BIOS in freqency/voltage section i can oly raise FSB but not the voltage (why voltage then in title?). And what is most irritating of all, if I raise fsb for just 2mhz (135/35/off value) my comp wont even pass floppy check(!?). On higher values it crashes while raising windows but it passes floppy (??!!), and on one middle value (140/40/off think) it passes all without crash but windows wont load, says my hardware has problem (!?).
Is board locked for OC? Can it have something to do with tbredA? (a guy sold me CPU and said it was tbredB, didnt know then where to see diference on CPU btw A&B, filthy sneaky dog!)