Sadly I share your frustration. It took me long enough to get Quicken 2004 running on Win7 as support in UK was withdrawn. I have also tried to inject some colour into the registers but with no success ..... sorry I can't help but will be watching your forum question in case someone comes up with an answer.
I also have Quicken 2000 running on Win7 and have reverted to using this which does allow colour changes. It is simpler than Q2004 ... the latter being yet another package which has developed features which most people don't need, but simply add complexity.
P.S. I am also a UK based pensioner.