There are such computers where the power switch on the front leaves it in a sort of standby-mode. It might have a 'real' power-disconnect at the back. Fully depends on the designer. See the user manual. Or post make and model here so someone may recognise it.
Does the system boot from a boot diskette (get a program to make one from www.bootdisk.com). Then use that to install Windows 98 on the hard disk on this machine. Something might be defective, but you will never know for sure until you try.
Ctrl-alt-del is a very uncommon way to get into the BIOS setup; you might find it for your system in http://members.cox.net/joemurphy/setup.htm or http://www.mustek.com/Support/techdocs/bios.html. Or tell more about the machine and motherboard to get help here.
I have this computer that did not have the O.S. intalled so when I try to install the O.S. and power the pc what I notice was this.
I have tried to turn off my pc by pressing the power switch, but it does not turn off when I press the power bottom, and it remains on.
The only way a can turn it off is by unpluged the power cable.
This is what I did. I removed the HDD and installed into another computer, and installed the O.S win98 then I put it back to the original computer but it does not boot up I try to power off but does not turned it off.
I check the fan in the back and it's working.
another thing that I notice was this, when I turn it on and if I try to go into cmos by pressing CTL ALT DEL it will not work.