Laptop powers on but won't boot/nothing shows on screen

I have an HP with Windows 7 and vision amd. It's bloody ancient but its all I have and can't afford a new laptop.

The screen died a couple of months ago so I was using an old flatscreen monitor which has been working fine.

Last night I was using the laptop and bumped into it, very lightly, causing it to shut off, which happens fairly frequently because the battery doesn't hold a charge, and the ac plug often easily loses its contact with the laptop, if the laptop is moved even a few millimeters.

So I fiddled with the ac chord and jack til the power light came back on and started the computer back up (as I've done dozens of times before). The difference this time was that though it powered on, nothing came on screen, and the monitor said no signal and then shut off. The caps lock, battery charge, and pcu light (light to the right of the battery light) all flash on and off. The pcu light is much more faint than the others.

I looked through and tried some of the recommendations on this site but to no avail.

I tried taking the battery out and holding the power button for 20 seconds. Tried troubleshooting the ram by taking the two cards out and trying different combinations in the two different slots. Nothing changed. I also tried covering the fans and powering on the laptop to heat up the video card but that didn't work.

Any other suggestions?