raspberry pi will not start up after i reset its card

[RaspberryPi guy2345]

Hey guys!
I was wondering if anyone can help me out here...

The problem is that my Raspberry Pi 3 Model B that I have purchased recently, needed resetting because I put its GPU to 7000 MB.
Now, not only it doesn't work after resetting the card, but when the 'No Signal' sign keeps popping up and disappearing after 2 seconds to try to reboot, but failing. I seriously need help here, please.
Thanks.
P.S: I cannot afford to buy another one, so, yeah...
P.P.S: I also heard that if you unplug all the wires and let it sit for 1 hour or so, it also works, but who knows...

[Burngate]

The "No Signal" sign is created by your monitor, not the Pi.

Unplugging and waiting is to allow the Pi's resettable fuse time to reset itself. It may help, until the next time the fuse pops ...

Have you tried Etching a fresh copy of Buster onto your SD card?

[RaTTuS]

Hey guys! ... needed resetting because I put its GPU to 7000 MB....

What does that mean ?
viewtopic.php?f=28&t=58151 <- see this