"I am trying to get an old computer of mine to work and whenever it boots up it says CPU is unworkable please check-CPU SOFT MENU I...."
Last night and today I was setting up an Abit BH6 mboard, for a friend whose mboard failed (bad capacitors), and trying a slot 1 PIII 450 and a socket 370 PIII 500E on a Gigabyte GA-6R7+ slotket card.
The BH6 mboard has "CPU SOFT MENU II" in it's bios Setup - your mboard may be an Abit mboard too.
Your message means the bios has detected the settings you are using for the cpu don't match the cpu type detected by the bios, and the bios is using default settings for the cpu type detected instead.
How did it get that way? If you didn't set the cpu settings wrong directly youself, loading bios defaults, or clearing the cmos, or flashing the bios will do that, or in some cases some bioses are very sensitive as to exactly when you press a key to get into the bios Setup, and merely doing that at what it "thinks" is the wrong time will reset your cpu settings.
You can also get the message if your mboard bios battery is too weak, or dead, or in it's socket upside down (usually + is upwards), or not making a good connection in it's socket, but in that case, the time and date would be set to defaults every time you booted the computer after having turned the computer off.
(If you DID flash the bios, you MUST load bios defaults in Setup after you flash - otherwise the settings you see in Setup may not be a match to those that go with the bios version - they may still be those for the old bios version - flashing the bios often does not load the bios defaults automatically.)
What you need to do is to go into the CPU SOFT MENU I in your bios Setup and choose the right mhz and fsb speed for your cpu from the standard choices provided, save settings, reboot.
I tried slightly overclocking the two cpus I tried, but every time I did, I got the "CPU is unworkable......." message while booting.
When I chose the standard settings, I no longer got the message.
If you're not sure which cpu you have, open up your case and use a good light to read the not so obvious grayish cpu mhz and fsb specs on the top of the slot one cpu, or if you have a slotket card with a socket 370 cpu on it, remove the fan/heatsink unit if it has a fan, or the heatsink if it doesn't, and read the same things on the cpu.
If you remove the slot 1 cpu or a slotket card, you MUST unplug the computer or otherwise remove the AC power to the computer, BEFORE you do that!
The slot 1 cpu or slotket card are often locked into the retainer brackets - see your mboard manual for how to unlock it.
Or - use the CPU ID utility available on the Intel web site.
The bios finds the correct cpu core voltage automatically.
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By the way, 98 and 98SE cannot run as they should unless you have at least 96mb of ram. E.g. If you have a spare ram slot space, many people who have older computers have 32mb Dram or SDram modules they aren't using and could give you - ask them.
I did some testing with Sysoft Sandra - if you have less than 96mb your hard drive cannot achieve it's max speed, and there is a lot more hard drive activity ("thrashing") accessing your virtual swap file, especially while booting.
128mb is a better minimum and works very well for most people's uses - you won't notice much difference with more than that.