Cannot get into BIOS on Dimension 4600 at boot

Try pressing the F2 key first when the machine is booted up to see if it will let you into the BIOS Setup.  If that doesn't work then try tapping the F2 key repeatedly when the machine boots up.

With a wireless keyboard you need to have the USB Emulation setting in the BIOS Setup enabled in order for the keyboard to be recognized during the boot up.  Otherwise the keyboard will remain inactive until Windows loads the drivers for it.  By default this setting is enabled when it comes from the factory although you may have changed it.  Double check to see that this setting is enabled.  Some Dell models have one USB port active during the boot up although I don't recall your model being one of them.  Try switching USB ports to see if the keyboard becomes active during boot up.  Otherwise use a PS/2 style keyboard to access the BIOS Setup.

With your model's BIOS the only setting that would speed up the boot time would be the Fast Boot option in the BIOS Setup.  Again, by default this setting was enabled when shipped from the factory.  In your situation a boot time of 2+ minutes is excess even with this setting disabled.

If you have any USB devices attached to the system like a printer, external hard drive, scanner, etc, try disconnecting them to see if it will speed up your boot time.  It is possible the system is trying to boot from one of these devices and that is the reason for the delay.

do you have a 2nd video card, i have 2 video cards on my dimension 2200 and it only shows the dell screen on the intergraded video not the pci one

Normally when the BIOS is loading during boot up the operating system doesn't come into play yet. To rule out Windows being a factor try an alternate boot up.  If you have a floppy drive or CD and it boots before the hard drive try inserting a bootable media into one of those drives.  A bootable floppy or the Dell Resource CD will boot up to the operating system found on the media and avoid Windows loading from the hard drive.

Nope - only one video card and nothing else unusual about the system either.  Could it be Windows power management conflicting with the BIOS power settings?  If so anyone got any idea how I can get into the BIOS???