Gateway GM5074b start-up problem

I have a Gateway GM5074b running Windows 7, graphics card GeForce 8500GT.

When trying to start the computer, the system powers up, fans audible and front-panel light on, and there's some initial noise from the drives, but the monitor remains on standby, and after the first 10-15 seconds there's no further sound of activity from the drives - aside from the fans, the system is inactive.

This has occurred once or twice in the past six months, but it resolved after leaving the system switched off for a little while. This time it seems to be permanent. I'm not sure which component is most likely to be the culprit in this case - if it were the hard drive I'd still expect the monitor to show something. My top candidates are the graphics card or the motherboard, but I'd welcome some advice in narrowing it down. Unfortunately, I don't currently have alternate components I could swap them out with to help eliminate the possibilities.

Update: It turns out I did have one alternate component option - the motherboard had an onboard graphics chipset, with a monitor connector that had been taped over by the manufacturer. After removing the graphics card and connecting the monitor to the onboard graphics, the PC started successfully.

So, it looks like the graphics card was the culprit. It's a GeForce 8600GT. If I replace it with a GeForce 210, which seems to be the current entry model, should I get comparable performance from it?

Thanks for the memory suggestion - it was a possibility I hadn't thought of.