PC is acting very strange

[StixuYT]

I firstly built this PC using new parts(other than GPU and CPU which I borrowed from a friend because he didn't use them anymore)
PC Specs:
R5 2400g
ASUS TUF GTX 1650
Gigabyte B450M K
Reddragon 700w full modular psu

When I finished the build, I was excited, powered it on..but nothing came on the screen, one thing I noticed was that the restart button was making the case fans go to 100% fan speed if hold, which was weird, I figured out it was the cpu, I removed it and I saw that it had a bit of thermal paste on some pins, I cleaned it off very carefully, and then I put it back in the PC, It booted up very fine afterwards, but recently, sometimes when I start my pc, I get past the gigabyte screen(it posts) but after it loads windows, I get black screened(Monitor going to sleep), Keyboard and mouse lights turn off, only the case fans remain, usually a restart from the button repairs this issue, but today, It didn't, I installed a game, and I wanted to restart my pc for some settings not to save(it's a weird scenario) but upon restarting, my screen went full black, monitor sleep, and mouse/keyboard shut off, nothing...it posts up fine, but when it gets to windows it acts strange, because if I press(or hold) the restart button again, it makes the fans spin to 100% again, I am currently using the PC just fine using Hiren's PE, its very low resolution, but it works, in normal windows it does not work whatsoever, what could be the issue? 

[StixuYT]

Managed to boot into safe mode and it works just fine...However, normal boot still doesn't work, I think I'm reinstalling Windows