Also,you decide what Windows I wll install.

Which games do you want to play using this computer?

The i810's integrated video is a weak 3D accelerator, based on the i740. For 3D-accelerated games, you'll want to add a PCI video card.

A pair of Voodoo 2 would be the ideal companions - hence the best OS for that is Windows 98 SE.

So,system is set to install-Windows 98 SE,as Automat said.Sadly I can't find any Voodoo 2s in here,plus the PCI slots are very limited as you can see.
STX,I mostly play 2D games,like Abe's Oddysee and Gamehouse games (Mad Caps,Chuzzle Deluxe,Ricochet Lost Worlds,Chainz,Bookworm and Beetle Ju)so the onboard videocard is enough,as I have played all those games and they really are 2D.
All of those,except Oddysee are going to be installed from a pendrive.I have made myself a driver&software kit for 9x/ME so makes life easier 😁
The only problem is that the NIC doesn't work.I have tried connecting my network cable and no leds light up. (the NIC has 2 leds and one of them should light up)

According to MobyGames, Bookworm requires Windows 2000 or greater, so maybe Windows 2000 should be your OS. Using Windows 2000 instead of Windows 98 SE shouldn't be a problem for you though, since all of the games that you listed have Windows versions. Is there a Windows "Certificate of Authenticity" sticker on the case?

Integrated NICs occasionally die even though the rest of the motherboard is fine. Just disable the integrated NIC in the BIOS and use one of your PCI slots for an add-on NIC.

PcBytes, your first priority should be to get your hands on a new camera!

badmojo,actually my first priority is to make my hands not shake!I used my tablet to take the picture,and I have used it to take pictures,they came out pretty good.Just my hands shake for no reason!
STX,the NIC isn't integrated,it's a PCI card.Oh well,no internet for me for some time.For the OS,Windows 2000,as you said Bookworm won't work under 9x/ME.The case doesn't have a CoA sticker,because it's a generic DeluX case,and no DeluX case has a CoA on it.I got the HDD and DVD to work correctly,finding out the IBM BIOS doesn't like the DVD-ROM being anything else than master,no matter what channel it is.I'll install the OS later,then post a few pictures.

What is the jumper on the back of the DVD-ROM drive set to? I recommend setting it to CS (cable select). Then, the BIOS should make the drive either Slave or Master depending on the drive's position on the cable. Also, make sure that you haven't plugged the wrong end of the IDE cable into the motherboard.

I made sure I plugged the correct end of the IDE cable.Also,tried CS and same result as Slave.Oh well,no problem if the DVD is master.

Huh. That's strange. Does the nonfunctional NIC work OK in a different computer?

I don't have any other computers than my main one (Sempron 3400+)and this one.I didn't try the NIC on my Sempron though.

Plug the NIC into the Sempron box. If it works there, then the GA-6WMMC7 is half-dead and ready for recycling.

Plugged it on my Sempron.Still doesn't work.It shows Network cable unplugged,like it did on my GA-6WMMC7.

Did you check the contact blades inside the connector socket?

I checked,they're fine.

Recycle the NIC. Just out of curiosity, what is the model of the NIC? (Is it a DFE-530TX? That's the only model of PCI NIC that has ever given me a problem.)

So, what do you need next? Windows 2000 installation files and a license?

IBM Etherjet PCI 10/100 is the NIC.(also named as Intel PRO 10/100 Ethernet Adapter)
For Windows,well I have a disc.All I need is obiviously a key,as I lost my old key.

Were you using that key with a Windows 2000 installation that hasn't been overwritten yet? If so, I think you can connect the hard drive as an additional drive in another PC and retrieve the lost key using Enchanted Keyfinder.

The HDD is completely new,and didn't had any system previously.