I'm having similar difficulties using XP Pro. Absolutely nothing I try will allow older games or those bought under the 'Sold Out' label to operate in compatibility mode. I've even found the occaisional game that is suposed to be XP friendly won't run either.
'signature' errors seem to be the most common, but I don't know what this is let alone a cure.
Any assistance would be appreciated. I can't help thinking that I'm doing something wrong.