Question PC won’t start but LEDs are on

Jan 19, 2021
Hello, long time lurker, first time poster. Recently my computer has been occasionally freezing to the point of not being able to process any request until its restarted. Previously, it only happened late at night about once a week, but the frequency of the freezes has been increasing. First it was once a week, then once a night, and now its happening during the day, interrupting my school ZOOM Call. I may be completely wrong, but i believe this is a result of my boot drive being an old HDD so I decided to try making my Samsung 970 EVO m.2 SSD my new boot drive.

I downloaded windows 10 on a fresh thumb drive and decided to reapply thermal paste on my CPU while I was at it, because I also suspected that might have been the issue as well. Im not sure what happened exactly, but whatever I did after this point messed up my computer. I disconnected my PC and grounded myself before taking off my CPU fan and cleaning the old thermal paste with a cotton ball soaked in isopropyl alcohol, after which i dried the CPU with a paper towel and reapplied the compound. I screwed the fan back on, disconnected my current HHD’s SATA cable and plugged the thumb drive in. Finally I set my tower upright, plugged in the power, LAN cable, and one of my monitors. To my surprise, when I pressed the power button it didn’t turn on, despite the motherboard and graphics card LEDs lighting up.

This is very puzzling for me because when I press the power button it doesn’t even momentarily turn on. No fan spins, no BIOS, nothing. I tried putting the CPU fan back on again, plugging my power cord directly into a wall, and reconnecting my HDD, none of which had any effect. Did I mess up when I put the Thermal Paste on? Could I have accidentally unplugged a vital cable? Please help, honestly at this point i would just be satisfied to get it back to its original state. Thank you!
Specs: ROG B450 mobo, 1060 6gb, AMD 3200, Samsung 970 EVO,TX650W Power Supply