Recently I've attempted to replace my old graphics card (AMD Radeon HD 6450) with a new one (AMD Radeon R7 250), did exactly what all those tutorials I've read about it said. Uninstalled old drivers, turned my computer off, took out the old car, put the new one in, turned my computer back on, everything was working fine, installed new drivers, turned my computer back off and on, but there was no beep and it shut itself off after a few seconds. Took the new card out and put the old one back in and the computer turned on normally, been keeping a close eye on it for a few days now and nothing unusual has happened yet.
Tried again last night and got the same result as a couple of days ago. I'm wondering what could be causing it.