Having some issues with my girlfriend's PC. She has this computer for roughly 10 years now and has become super slow to the point of taking more than 10~15 minutes to even load it to the desktop. So I decided to take some time and clean it.
Decided to start by cleaning all the gunk and dust. I'm no expert but I do have some knowledge of how to open and clean laptops.
Removed everything carefully, took out the mobo, removed the fan, cleaned it well since it had clogged up with dust, and removed the old thermal paste and applied a new one.
After that, I proceeded to mount everything back, making sure that the cables were well fitted. Before placing the remanding components, I decided to give a test to see if everything was OK. The PC turned on with the no OS disk found screen. Turn it back off and finish mounting everything. Before screwing back the screws, I gave it another test and this time the PC wouldn't boot up. The only thing that happened was a single blink on the power up button. Took a few steps backwards and tested it again. The same results, single blink on the power button. With the battery and power cord, there was an orange led. With the battery out and the power cord on, the led was white. So there's no faulty power cord nor faulty battery.
Searched the webs and proceeded to do some solutions on others threads. Taking the battery and the power cord off and holding the power button for a couple of seconds. Then holding the power button for a minute, hold the same result. Tested the PC with one component at the time to see if any were faulty, the same results. I even tested the HDD on a different computer and it would read its contents.
Decided to stop for that day and give it a try the next day.
Proceeded to do the same solutions and still no result. I took everything out again and slowly put one thing at a time, and tested to see if the PC would boot up. With everything out except the MOBO, plugged in with the power cord, it would boot up to a black screen with the fan spinning. If I placed any other component, the PC wouldn't boot up. Still giving me the single blink.
I did a bit more research and a few threads mentioned the CMOS battery, but that wouldn't cause the PC not to boot up or would it?
Would gladly give more information if needed, just unsure on what could it be.