Hi, I have a HP ze4540us laptop. 2.4mhz intel mobile cpu (not celeron) 1gb ram 40gb hdd cd/dvd internal wireless card. Something shorted out a while ago, and the MB died. I bought a used MB off ebay, hoping to get the thing back up and running again. The new MB is from a compaq presario 2100, and has the same part number as the HP MB I was looking to replace. I didn't buy a tested-and-guaranteed-working MB because the prices are higher than the current value of the laptop. So I am looking for a cheap DIY fix. The new MB has an intermittent power failure problem, I have had times where I can get it to boot up all the way into windows XP, and function properly until I shut it down. Mostly however, when I try to power it up, the computer begins booting for about a second or two, and then shuts off for about 3 or seconds; and then repeats this process for about a minute, after which it just stays shut down. During these short "on and off again" cycles, the computer never reaches any kind of display screen at all (no post/bios). I have tried reseating the ram/hdd/dvd, resetting the cmos; removing just about every removable component, and attempting startup. Any suggestions on what is going on with this mb, and is it repairable, or should I just give up and look for another mb?