Question on A/C system

["Steve Rubano" <srubano@xxxx>]

Hi all, I was wondering if someone out there with A/C system 
knowledge can give me some advice. The A/C system on my car has 
been "dry" for some time now (don't know how long) where as all the 
freon was out. I am assuming there is a leak somewhere. There was no 
hint of pressure at all when I was taking it apart. Here are my 
questions:

1. What should I suspect/check on my system that would go bad from it 
being dry for some time now?

2. Is the new "legal" freon as cold as the old stuff? I have only 
dealt with the older stuff so I can't compare the two.

3. Can I check for leaks in the system without charging it with 
freon? I know that there are special UV Dyes out there you can inject 
into the system and use a black light to track the leak. Can I use 
this without charging the system or do I have to charge it so I can 
run the A/C to find the leak?

Any info would be appreciated, thanks.

Steve