Motherboard Powers Chassis Fans But Not CPU Fan

you did not plug in your fan correctly or you have a bad cpu fan

Oh right, should've mentioned. I've tried about three different fans, I know it's not the fans because when I used the fans in a different computer, they worked fine, and I know I plugged them in right (How do you manage to improperly plug a CPU fan in? The clips won't even let you do that...)

have you tried going into your bios and setting the cpu fan to manual mode [full speed], if not just plug the 4 pin into a 3 pin chassis fan. if that doesnt work you might have a bad fan

The motherboard is a factory motherboard from HP. Can't really do anything about fan speeds, and then there's the fact that this AM2 motherboard only has 3-pin fan headers, and I have tried with 4-pin ones as well, and as I said before, I've tried more than one fan, and those fans have worked with other computers. It's not the fan. What I find odd is that any CPU fan that is plugged into the board won't work but if I plug a chassis fan in, it'll work.