What does the Dimension 3100C have to do with this?

How far is the Dimension 9150 from the router?

Dimension 9150 has its own Network Adapter (Ethernet) port on the back. So why would you want a USB>Ethernet dongle? Connect the Ethernet port on the 9150 directly to your router using a CAT5 or CAT5E (or better) Ethernet cable.

If you're saying your router only has one Ethernet port, and that's already connected to the 3100C, then you may want to consider a new router with multiple Ethernet ports.

If the 9150 is far from the router and/or there's only one Ethernet port on the router, you might consider a USB>WiFi dongle (assuming the router has WiFi capabilities) but Ethernet will be faster and more reliable than WiFi.

Hope you realize that XP is long past its "end of life", and there's no support for it. It likely has a bunch of big security holes that Microsoft never fixed, and most "main-stream" browsers (Firefox, Internet Explorer, etc) don't support XP any longer either. And most anti-malware apps also aren't supporting XP. So PCs running XP are vulnerable to attack on the internet.

Thanks, Ron, for taking the trouble to provide such a clear and comprehensive reply.

The two machines stand next to one another.

The router works fine on the older 3100C machine. However, when I transferred the router connections to the 9150,no access was provided to the internet.

I think I will follow your suggestion of using an ethernet cable (I am grateful to you for defining the required specification) and see what happens.

I acknowledge that Windows XP is now almost obsolete, and I intend to upgrade to Windows 10 if the little-used 9150 seems to performing OK in other respects.

Thanks enormously for advising me - my knowledge of IT is feeble, to say the least, so your guidance is greatly valued.

Can we assume the 9150 boots into XP normally, even if the NIC isn't connecting?

Reboot the 9150 and immediately press F2 to open BIOS setup. Find the Integrated NIC option and make sure it's set to ON (not to any of the other options). Save the change, if any before exiting setup.

Make sure the NIC cable is connected securely at both ends. You probably should see some small LEDs on back panel near where the NIC cable connects to PC. Are any of them lit when PC is booted to desktop and connected to router? You probably should see at least one, possible either orange or green, and a second one that's blinking...

Open Windows Device Manager and look for the NIC entry. Is it set to enabled and not marked with an ! or X?

Did you reboot the router after switching cable from the other PC to this one?

Did you run the Windows XP Network setup tool to configure the 9150 NIC with the router after the two are connected? 

Did you try the Windows XP Network troubleshooter?

Is the 9150 compatible with Win 10? There's no free upgrade from XP to Win 10, so you'd have to buy a Win 10 license from Microsoft, assuming PC is compatible. And even if it is, you're limited to 4 GB of RAM in this PC model which is barely adequate for Win 10.

If you use CAT6 cable it should work on anything.

Any Cat3 cables should be thrown away.

https://www.amazon.com/AmazonBasics-RJ45-Cat-6-Ethernet-Patch-Cable-14-Feet-4-3-Meters/dp/B00N2VJ2CG/

• 10 Mbps = 1.2 MB / CAT3
• 100 Mbps = 12 MB/ CAT 5
• 1.0 Gbps = 125 MB/s CAT6
• 10 Gbps = 1.25 Gbps CAT 7

CAT 3 is the old standard and not forward compatible.

CAT 5 is newer but is only 100 meg

CAT 6 is newer and works with 10 100 or 1000 meg

CAT 7 is for 10 GIG connections which you do not have.

Thanks, Speedstep,  for that very specific information. It's very helpful and nudges me a couple of rungs up the learning calendar.  At this rate, I'll  have become an IT expert by the end of the month!

Thanks once more RoHe. There's a lot of info there - stuff I'd never have thought on my own. I think I understand most of it and I'm going to get to work over the weekend. I'll be crawling about on the floor like a baby as I grapple with the various cables, controls etc. Looking forward to it .Will report on progress asap. Thanks again (and also for the further comment re limitations of the Dimension models when it comes to Windows 10)..

If you Google, you'll see some say the Dimension 9150 can't run Win 10 and others say it does. So flip a coin. :Wink:  Dell doesn't support Win 10 on this model, so you'd be depending on Win 10 to provide most/all of the drivers you'd need.

You could create a complete image of the hard drive with XP on external media (USB hard drive) with something like Macrium Reflect (free version) and then see if you can install Win 10.

You'd need to download the Win 10 ISO file (free), and create a bootable USB stick. If Win 10 installs, it won't be activated but then you could purchase a license for it. If it fails, just revert to the XP image you created and you've only spent time, not money.

Dell doesnt support WIN 7 or 8 or 10 on 2006 Optiplex GX620 either but it works Just fine.

You need AT LEAST a Pentium D 915 to run 64 bit windows 10 due to the LAHF SAHF  CMPXCHG requirements.  ALL VENDORS are DROPPED SUPPORT for 32 bit OS and Apps. October 2018, AMD no longer offers 32-bit drivers. Nor does INTEL, NVIDIA, etc.  If you have a Pentium D 830 series a 915 or newer is easly had via ebay or amazon.

The GX620 is unique in the fact that it supports both SATA and IDE and runs MSDOS all the way thru Windows 10.

https://www.amazon.com/Intel-Pentium-SL9DA-dual-Presler/dp/B009YPSYJG/

There is no reason a machine that is 2006 or newer cannot run 10.

HOWEVER  newer Radeon Video cards aka the R series DO NOT WORK.

NVIDIA seems to be fine even with Ancient Dells Up to GTX 1080 TI.

https://www.youtube.com/watch?v=qa9b0TkTsLM

In the video he has a  Dell Dimension 9100/XPS 400 FJ030 ,YC523

http://downloads.dell.com/published/pages/dimension-9150.html

Bios and Audio Driver are the only "needed" items.  Those who say it doesnt work are having Issues with Older than Pentium D 915 processors.

Earlier Smithfield CPU's work but ONLY with 32 bit windows 10.

Prior to that the cpus don't support NX so they wont work with windows 8 or 10.

LAHF SAHF CMPXCHG 128

Description	Supported OS	Download
SIGMATEL STAC 92XX C-Major HD Audio, v.6.10.0.5343, A02 Sigmatel STAC92XX C-Major HD Audio DriverMore details	Windows Vista 32-bit Windows Vista 64-bit

Description	Version	Download
Dell Dimension System BIOS, A07 Dell Dimension DXP051 A07 System BIOSMore details	A07

https://www.youtube.com/watch?v=PMO1AE8QoNU

Thanks speedstep for supplying such comprehensive information - huge respect!

Unfortunately, some of it is beyond the extent of my brainpower which is embarrassing for me.

Others have also been kind enough to provide much-appreciated advice and knowledge.

Frustratingly I haven't quite got things sorted yet, but my stepson is visiting later this month. Hopefully he will be able to synthesize the information in all the replies and get the problem Dimension linked up to the internet.

Thanks again to everyone for all their kind help. It's hugely valued.