|I couldn't find any significant info about ABIT KV7A , but going by similar ABIT mboards made around the same time, it's probably very similar to this except it has the A revision of the same Via northbridge:|
Make absolutely certain you do NOT have a metal mounting post mounted in the case at a place where there is no mounting hole in the mboard ! In that case the mboard can easily be shorted where the errant mounting post is.
Of course, make certain all your connections are correct and all connectors are fully seated.
Make sure the ram is and all the cards are all the way down in their slots. You could try removing the ram, installing it again.
On many mboards, you MUST have a 3 wire fan connected to the 3 pin cpu fan header, otherwise the mboard will shut down within a very short time when no rpm is detected from that header to prevent the cpu from burning out. If you do have a cpu fan connected to that header but you changed it, the bios has built in defaults regarding what rpms it expects - if the new fan spins slower the bios may not detect it's rpm or may detect it as spinning too slow.
ATX mboards are always being powered in some places by ATX PSs, even when the computer is not running, as long as the PS is connected to the mboard, the switch on the PS is on, if it has a switch, and the PS is receiving live AC power.
You should ALWAYS remove the AC power to the PS whenever you are going to be connecting or disconnecting anything to the mboard when the PS is connected to it, or the to PS itself.
The switching PSs used in computers must have at least a minmal load on them when you start them up. If you start them up when they have no load or not enough load on them, they may be damaged.
If you did not do that at ANY time, you may have damaged something, including you may have fried the PS itself.
E.g. I fried one PS by merely connecting a hard drive to it when it had live AC power (it was already connected to the mboard and other drives - I suspect I fried it's controller chip).
Your PS may be fried.
They often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way.
If you have another working PS you could try, try that.
This mboard would work fine with a PS that has a (output) capacity of 250 watts or more.