cannot reset an old 2000 imac

That's right, resetting a 2000 iMac is a bit different from newer models because it predates features like Recovery Mode.Here's how to approach it:

1. Identify the Mac OS:

Since it's a 2000 model, it likely came with Mac OS 8 or Mac OS 9. This information might be printed on the back of the iMac or you can check inside the System Preferences once booted up.

2. Reinstallation Discs:

The ideal method is to use the original Restore CDs or DVDs that came with your iMac. These discs contain the specific Mac OS version for your machine.

3. Retail Discs (Alternative):

If you don't have the original discs, you can try retail copies of Mac OS 8 or 9. Be sure to get a version compatible with your iMac's hardware.

4. Booting from Disc:

• Insert the reinstall disc (original or retail).
• Power on the iMac while holding the "C" key.
• This should boot from the disc and begin the installation process.

5. No Discs?

Unfortunately, reinstalling the OS without discs becomes more complex. Finding legacy versions of Mac OS online can be risky, so proceed with caution if you go down this route.

If that iMac dates from 2000, that would make it one of the early CRT-based iMacs with a PowerPC processor.

Holding down Command-R at startup time isn't going to get you into Recovery Mode, because Recovery Mode was not a feature of PowerPC-based Macs, or even of the first few Intel-based Macs and versions of Mac OS X. You are going to need the recovery discs that came with the machine, or retail Mac OS 9 or Mac OS X discs, to install an OS.

To start up from an optical disc, you would insert the disc and hold down "C" at startup time.

MacTracker says that the "iMac/iMac DV/iMac DV+/iMac DV SE (Summer 2000)" were introduced in July 2000, and discontinued in February 2001. The original OS was Mac OS 9.0.4 (Classic Mac OS). The latest OS they could run was Mac OS X 10.3.9 ("Panther") for the 350 MHz models or Mac OS X 10.4.11 ("Tiger") for the 400+ MHz ones.

Given changes in Web security protocols and other Web standards, you'r not going to be doing much Web browsing with that iMac – but it might be interesting resurrecting it for historical interest, or to run old games.

If you search the Web, you can find lists of startup key combinations that work with PowerPC-based Macs, e.g.,

https://www.macintoshrepository.org/articles/27-powermacs-key-combinations