My computer lives once again... but for how long?

Last week I turned it on. The monitor came up with the manufacturer's logo, then displayed a "No Signal" warning and went into power save mode. A few re-boots proved that this was a repeatable condition.

I have a spare video card I keep on hand for just such an emergency, and when I installed it, I got the same results: no video, no signal.

Okay... put the original card back in, connect it to a different monitor. Same results: no video, no signal.

It was looking more and more like either a bad HDMI cable (I don't have a spare for that) or a bad motherboard. In any case, I'd reached the admittedly small limit of my expertise, so I took the computer and cable to the local repair shop and let them play with it. Somewhat to my surprise, they found the problem and fixed it. Sort of.

The problem turned out to be a failure of the PCI-E slot on the motherboard. There was another PCI slot still available, they moved the video card (an NVidia 8600 GTS) to that slot, and the computer now works. I didn't ask for details, so I don't fully understand why, but the tech said I would see reduced video performance with the card in its new location. Something about PCI-E vs regular PCI or something like that.

They had the computer for two days, the repair bill came to a staggering 250 pesos, or about twenty US Dollars.

The tech said that I would do well to start researching and looking for a new computer, because he said it was quite possible that this problem was only the first of a cascading series of failures.

So, now the question: Do you think this was an isolated incident, and life for my eight-year-old computer can go on, or am I likely to soon experience more and similar problems?

Second question: Since the video card is in a new location now, every time I boot up Windows I get the dialog box saying there are no video drivers installed. I have downloaded (but not installed) the appropriate drivers from NVidia's website, but except for that dialog box from Windows, everything seems to be working: I can pull up the NVidia control panel and change settings, etc. I'm pretty much of the school "If it ain't broke, don't fix it." Should I install the new drivers (150+ MB of them!) or leave well enough alone? What do I do in order to install them anyway?

FWIW, the OS is Windows Vista, SP-2. This is the original 8-year-old installation, and is rock-solid. There has been so much software installed and removed over the years that the system registry is pretty bloated, and it takes more than five minutes from power-on to usability, but is great after that.

If I do need a new computer, what would you recommend? I know, that's like asking "How high is up?", but in general what should I look for? My current computer, even though it is eight years old, is still a pretty decent machine: dual-core 3GHz processor, 4 GB RAM, 4+ TB across four hard drives, 256MB on the video card, SoundBlaster sound card, six SATA slots, six USB ports, HDMI & VGA video out, parallel and serial (!) ports, E-SATA and FireWire, etc. There are seven cooling fans inside the case, if you count the small fans on the CPU and the graphics card. As you might guess, some small form-factor, stripped-down non-expandable computer is not what I'm looking for.

Ideas?

tanstaafl.