Ed -

If you think you may have a hard drive failure coming on, you should immediately print yourself a copy of Q166172 Duplicating Windows 95/98/98 Second Edition Installation to a New Hard Disk from the Mickey$oft Knowledge Base, and make the appropriate backups. It is possible to transfer your existing setup without a lot of reconfiuring, but you have to plan ahead.

If you have an available set of connections on your disk controller, you might consider installing a second drive before the old one fails, just so you've got someplace to save things while they're still there.
A simple-minded reading of your first post is that you have a boot problem. Win98SE should not ask you to insert a bootable floppy unless
- worst case: it can't find the boot sector on your hard drive, or
- trivial case: there's a floppy in the drive when it tries to boot.

Plug and play isn't great on Win98SE, but it should not stop a boot because of a device conflict. It should ask you what to do about the conflict, perhaps. In most cases, it should finish the boot and then give you an error message.

Your second problem is that the system shuts down - and tries to restart - when you don't expect it to. Most Win98SE system failures result in a "lockup" with the blue screen, black screen, an error message, or simply with all inputs "frozen." You have to "intervene" to force it to shut down and reboot. There are very few circumstances where it will attempt to "reboot itself."

Your third problem is that you have noises.

Of course, any time there's a problem, the first thing we should all do is run a virus scan from an up-to-date signature file. 'nuf said.

Unless you have deliberately set up to boot from a floppy you should be able to boot from your hard drive. If it doesn't boot there, that's probably the first thing to try to fix.

The most likely cause of unexpected reboots is the "ecologically correct" power management sytems that have been added to recent machines. Check "Start-Settings-Control Panel - Power" for any settings that you don't want. Different manufacturers put different stuff here, and none of them will give you a clear explanation of what it's all for. For the most part, my advice would be to turn everything there "off" - i.e. don't let the machine "sleep," "power down" or anything else based on these settings.

A less likely cause, mentioned above, is system overheat that causes a thermal protection device to shut things off. If these devices ever trip, they usually degrade so that they trip more easily the next time - so they can cause a progressive condition where things just keep getting worse. It is possible that you have a real overheat condition if your fan is failing, or even from something as simple as new NIC card being in a slot where it blocks the air flow.

A third possibility is that you have a "dirty" power circuit that has frequent momentary drops in the power. With an adequate power supply, the "hang time" is usually sufficient to ride through any dropout that isn't obvious - as in "you're in the dark;" but if your power supply is marginal, the system can drop out on "interrupts" that don't even dim the lights visibly. This is one of the few "fairly common" malfunctions that will cause an unexpected reboot.

The most common cause of unexplained "noise" from a PC is the fan. You should certainly check to see that it's clean, that it runs, and that the blade doesn't wiggle. Replacement is cheap, and usually quite simple. Some systems have the fan (or a fan) buried in the power supply where it's harder to get to, and quite a few systems these days have both a power supply fan and a separate case fan. You'll have to look.

I assume that the NIC you installed to connect to your cable modem is an etherlink card. As mentioned above, there are some known problems with using two identical cards, but they are not common. In the most common setup, you need one hardware device to connect to the internet, and a separate device to connect to your LAN, both in the machine that makes the connection to your internet service. Either hardware device is commonly referred to as a NIC. Your internet NIC can be an etherlink card, a USB port, a modem, or any of several other things. In most cases, your LAN NIC will be an etherlink card.

You need a Network Adapter (NA), which is the software driver that controls a NIC, linked to whatever piece of hardware connects you to your LAN, and a separate NA linked to whatever device connects you to the internet.

As long as one of your machines connects directly to your internet provider, you can connect other machines using a simple hub.

An alternate approach is to connect all of your machines to the LAN through a ROUTER (which replaces the hub), and connect the router to the internet service. This is the method that you pretty much had to use prior to the introduction of Internet Connection Sharing (yes, they call it ICS) with Win98SE and later. It is still probably the preferred method for larger networks, but for most of us it is vastly more complex to setup than the ICS method described above. (It's "simple" once you've done it, but it's tough for a "novice" to get straight answers about it. It also makes it easier for your ISP to require specific setup on your machine.)

If you need a "refresher," you can get a fairly good summary of how to share your internet connection most simply in Q234815 "Description of Internet Connection Sharing." The article is somewhat "dated," but has most of the essentials.

John