Sony Vaio VPCEB3L1E not POSTing

Hey everyone,
I have been searching for 4 days for anything that will work so I finally decided to ask directly. I have got a notebook from a friend to clean it up for him. It is Sony Vaio VPCEB3L1E. I first, have done some basic SW cleanup (formatted everything, new windows, drivers etc.) Then I did HW cleaning (disassemble everything, clean fan, change thermal paste) I have been doing this for past 5 months everyday on every kind of laptops. Then I assembled it all together and turned it on. Everything was working, I've got to Windows but I have heard some high pitch sound, I thought it was fan or something because it was doing it regularly, you know like every single revolution of the fan, not just random sound, so I was like wtf I just cleaned it and then the laptop froze. Everything worked, it was just frozen, so I obviously turn it off by holding power button. Now the laptop won't get even to POST state. Current is flowing beacuse fan is spinning, dvd-rom can be opened, I can hear HDD, but screen is blank. Nothing. Then I've tried everything like reseating the heatsink, reflowing the GPU, using different RAMs in different slots. Last three things I am not able to test if they are the reason nothing is working is CPU, Motherboard and BIOS. CPU still produces heat however, I know it is not sign it is working just "it's something". Keyboard's LEDs are not flashing once (it might be sign of corrupted boot block), and laptop now after turning on spins fan to maximum after few seconds and keeps either restarting or turns off. I know it looks like it could be overheating but I have no idea how and the paste that has been there was so dry I don't even know how it could be cooling in a first place. Now I need to somehow reflash the BIOS via USB (there is power in USB but I am not sure if it is really working) without the need of seeing something on the screen as it is blank (no, external monitor is not working as well) and also the main keyboard is not working so reflashing without any input? I did not try plugging some external keyboard via USB though. Just if any of you has some experience with reflashing BIOS on Sony Vaio. There is not even official downloadable BIOS, but one dude on some forum uploaded his and he had the same laptop as I do. Thank you for your help.