Hi ponygirl,
Well, you're running the latest operating system from Micro$oft, so that's a start I guess.
I would begin by updating the uPnP (Universal Plug and Play) driver, which is part of Windows, so you would want to install Service Pack 2 (don't know if they've already released 3 and refuse to visit their Web site. Sorry), and any / all security fixes plus any updated uPnP driver available from their site.
This may solve the problem.
(dh must use Win98 update to check he is up to date with OS security fixes / patches etc.)
The USB to Ethernet dongle's driver may be the cause of the problem. You would need to go to Belkin's Web site, look up that adapter, and download the driver for it to your hard drive. I've just had a look and couldn't find the driver for it but believe this is the product page. Possibly it has no driver. You will need to google the product number.
After that I would look to install an updated driver for the Speedtouch 510.
I appreciate if you're not properly broadbanded this will be immensely painful, so try and do the downloads perhaps on the most stable computer.
If you feel all the drivers are fine, possibly your crashes are being caused not by dodgy new hardware but by some nasty virus or spyware app on your PC.
You need to make sure your anti virus program is up to date and run a scan.
Same for your anti-spyware program.
Traditionalists would finally suggest cleaning up the hard disk with Defrag / Disk tester / whatever those horrible apps are now called...
You could also google Speedtouch 510 / blue screen and see if that gets you anywhere, or call the ISP who sold you this equipment.
HTH
Sorry I can't spend more energy on this, but supporting Windows literally saps the chi from my soul. The system is so hard for ordinary people to keep up to date and running smoothly it's a friggin joke. To update Mac software you click one button. It has no viruses nor spyware to speak of. As only one company (Apple) make the Mac, the hardware is a 'known entity' so easier to diagnose from.
I hope you sort everything out. Post with any specifics, and if I'm awake, and my soul has not been sucked dry, I'll try and help.