Hi, i'm currently having a big problem with my pc and need some suggestions as to what might be causing this problem, and any possible solutions. I'm going to try and be as specific as possible with this. System Specs: PIII 750mhz Abit BE6-II motherboard 3 HHD's Matrox Video card SB Audigy Sound Card 3com ethernet card cd-rom floppy promise HD controller card 512mb pc133 ram Heres the deal... I normally run my pc 24/7, this ones been going good for about 2 years now with no problems. The other day I come home and move the mouse to get the monitor out of standby but nothing happens. Then I notice there is no power to the mouse or keyboard (lights were off) but the PC fans and stuff are still running. So i reboot thinking it just froze, everything boots up as normal but after a few mins the monitor goes into stand-by mode, and the power to the mouse and keyboard turn off. But the PC remains powered (at least the fans do). From then on this happens every time I use it. Randomly it just switches off. So, I make sure i didnt have any weird power seetings set, then I view the system logs and see that an ACPI (Advanced Configuration and Power Interface) error occurs at the time this happens. So I disable ACPI in both windows and in the bios, and try again. Still the same thing happens, only now no error is logged. I also tried looking for any info on this error but couldnt find any that related to my problem. (most of them were problems with brand new motherboards, but i've been using mine for quite some time now) Now, after having this happen over and over, some other strage things happen. I would try and power on the PC and the fans and HDD's would start up, then you would hear them loose power or speed, then gain it again like the power flow to them were being fluxuated, until they finally stopped for good. The monitor would also not even come out of stand by mode during this. So i unplugged everything besides 1 HD and 1 Fan and after a few tries the system was able to boot up. Sometimes it'll start to boot then just run out of jucie, sometimes it'll make it into windows then freeze with glitches all over the screen, and sometimes it'll boot all the way up then shut down randomly. Now the weird thing is, I have not made any hardware or software changes lately. Nor have I ever had probems with freezing before. I'm currently in the middle of a big web design project for a client so I havnt had time to install anything new on my system or change any settings or anything because i've been busy doing that. Also, you dont have to be doing anything to make the computer shut down. It could be sitting there doing nothing and it will happen. I've tried booting up with nothing but a video card,ram,and 1 HD installed to see if something was conflicting but no luck. One solution i tried was buying a new power supply becaues i figured mine had failed, but that wasn't the case, then same thing happens with this new more powerful power supply. I'm assuming since this just happend out of the blue (and while I was away) that some piece of hardware like the motherboard has messed up? I just wanted to know if anyone had any ideas on how to fix this, if it is a piece of hardware that needs to be replaced such as the mobo then thats fine, i just want to know if thats it for sure before i purchse one (which i'd probably buy a new processor and RAM for too). I just now tried to boot up the broken PC and the fans came on, but the monitor didnt. then the HDD started powering up and spinning then started making a high pitched noise like it was struggling to move. ( I also have tried booting from other HDD's, they all do the same). I have had a few friends look at it, and they suggested things that have to do with changing bios settings or flashing it. I've tried a few but none have worked. The only problem with these fixes are that they involve doing something thats changing a wrong setting,but since the settings are all the same since day 1. I dont see how they would just now start causing a problem. So anyways, I hope I was specifc enough and any suggestions would be appreciated. Thanks!