BleepingComputer.com: How Do I Get Out Of Ms-dos Compatibility Mode

Inherited a HP Pavilion xt953 desktop computer and it is always operating in Dos Compatibility Mode.
I was going to try and use the HP Recovery Disks to see if that would help, but cannot, as I was ill advised to delete any reference to Easy CD Creator and other CD and registry files - thus my CD drive is unavailable. My Device Manager shows no CD and the Floppy Disk Controller along with the Hard Disk primary and secondary Controller are showing yellow exclamation points. Anyone have any ideas or know of another forum that might be of help. Thanks.

Here is some info from MS that might help. Yes, your screwed up device drivers are probably the cause. Here is more from another site.

Herk - Thanks for the input; much appreciated. It looks like I may be in over my head here, but I'll just go at it slowly. Your reference to "may have screwed up device drivers" interested me. What 'device drivers' might they be and where would one find them and install them, as my CD is not being recognized.

I was referring to the primary and secondary hard disk controllers in the Device Manager. No controller - no recognized disks.