While I was trying to install my new graphics card (ATI Radeon HD 5750) onto my old dinosaur of a computer (HP m7570), I followed the instructions step by step as follows:
1. I disabled my onboard graphics
2. I turned it off, put the graphics card in the PCIe slot and plugged in the power
3. I plugged my monitor into the graphics card by using the included DVI to VGA adaptor.
But when I turned on my computer again, the monitor was black. I think the problem stems from either my old motherboard, which only had a PCIe 1.0 slot while the graphics card is a 2.1, the adaptor might not be working as it should be, or maybe something else. I know it's not the power supply since I bought a new one (650, more than the recommended 450).
What could be the problem? I'm not a professional, so any help or input is appreciated.