Maybe something’s just acting up with that Windows XP installation disc, or perhaps the optical drive itself is starting to give out—like the laser might be getting weak. It might be worth trying a different version of the media to see if that fixes it.
You'll need to check the sticker on the bottom of the machine for the manufacturer and the specific model number. Just a heads up, you won't be able to install Winse directly onto the laptop's internal hard drive; you're going to have to run the installation via a USB drive instead.
Here, give this a shot. Try downloading the graphics driver directly from NVIDIA's site; it should be smooth sailing. Just hit *AGREE@DOWNLOAD and then click Save file http://www.geforce.com/drivers/results/77227#
Maybe the issue is actually the DVD drive itself. You might want to try borrowing another one or just swapping out the SATA cable connecting it to the motherboard.
That shouldn't be underpowered at all. So why aren't you just running the latest version of Zoom Play Player like Benjamin King2 suggested? You could just turn off that screensaver if it's causing issues.
Maybe try grabbing Hiren's BootCD. If you boot from it when you're starting up the PC, you can run one of those antivirus or antimalware tools to scan the system.
Hold on, Lucille, if everything was working fine six months ago, why are we back at square one? How often is this actually happening—is it just once a day or are we talking ten times? Also, what do the temperature graphs look like? Maybe try testing it out in a different browser, like Chrome, just to rule things out.