Today I started on my first build. I installed an amd phenom processor and after market heatsink onto an Asus m4a88t-v motherboard. I was able to boot it up outside the case with the ram, cpu, and gpu hooked up. After that I plugged 4 of the case fans onto 1 of the molex to 4 pin fan header cable provided by my psu. The cable has 4 molex plugs located across its length, so I figured it would be ok. After I had everything installed, I powered on, it would start up, then turn, so I took everything part and was able to get it to boot again with just the cpu, cpu fan, ram, and gpu. As soon as I plugged the case fans back in and turned it on though, smoke started coming from the molex cable, and I quickly unplugged the power cable. The cable didn't look too damaged beyond the rubber looking a bit melted, and I didn't feel any heat coming from the cpu. But now the motherboard won't boot, and I'm afraid I may of fried it. If anyone knows what exactly the problem could of been, and any details and what the damage is, I'd really appreciate it. Also any tips on maybe how to fix it or things to try to get it to boot would be great. Thanks.
Still, I would never expect four case fans to overload a molex cable - even if each fan drew 2W, you're only talking 8W - that's a pitiful total - a single 3.5" hard drive can draw more than that. Makes me wonder if you got a short somehow - a short would explain the smoke, but it wouldn't explain the failure to boot thereafter.
Good luck with it - sorry, I cannot suggest what you try next.