>Does the registry will be removed (especially the tcp/ip one)?
Removing your network adapters and your connection settings won't remove your entire registry, it will, however, remove the keys that were established when you set up the hardware and established your settings. Removing the hardware from Device Manager and rebooting will result in Windows redetecting the interface (assuming it's P&P) which will subsequently recreate the values in your registry.
>Driver irq least or more
"IRQ Not Less Than Or Equal To"? This error can be caused by several things. If you don't often see it (and I'm assuming you haven't, since you said it's the first error of the type you've seen), it's more than likely the result of either a corrupt driver or (as is usually the case) some wildly malfunctioning program that even Win2k's kernel couldn't control. It can, however, be caused by a deeper problem: IRQ conflicts. While normally Windows can handle them and make everyone play nice, a few cards and some drivers aren't so amicable. The one that instantly springs to mind is the SB Live. Though a solid card, it throws an absolute fit if it's not installed correctly. If the error persists, I'd suggest rebooting your computer and taking a look at the system information that you see (you know, it'll have the name of your BIOS manu. above a table that lists information about your proc and such). Down below you should see a listing of everything you have installed on your motherboard, it'll most likely have things labeled
"Multimedia Controller (some values) 5"
"Mass Storage Controller (values) 10"
or thereabout. The last value is the IRQ. If you see any conflicts (that is, two different pieces of hardware with the same number) you can either physically move the card to another slot, redefine its IRQ in your BIOS (in the case of COM ports and such) or, if need be, manually assign an IRQ to each PCI slot (it's usually labeled something like "Force IRQ Slot x: n") I'd suggest moving the cards phyisically though, should the need arise, as it tends to work a bit better than forcing an IRQ.
>How can i delete it and reinstall it???
The registry? In Win2k the registry exists in multiple files known as the "hive." Though there are ways to delete all the files that comprise it and allow them to be rebuilt, I wouldn't recommend it, as doing a reinstall of Win2k is a good deal easier. Of course, you'd need to reinstall your apps and such, if that were the case...
Anywho, if removing your networking info and reinstalling it results in your error disappearing, don't worry about it. Good luck.