How to make game use second cd drive

It is most likely looking for the drive it was installed from. Have you tried uninstalling the game and installing it from the ISO? You can also try to do a search of the registry. If you are lucky it will be something obvious and you'll just need to change the drive path.

Many games use copy protection where you can't run them off the ISO.

Did you buy a legal version of the game? If so, why are you trying play from a mounted .iso in the first place?

A game will look in the drive it needs to to run, you can see this by installing a game legally on a computer with 2 drives and it'll work fine.

The reason this is not working is because you are using a virtual drive and the copy protection on the game will prevent this as it cannot recognize the mounted 'disk' as legal.

The fix for this is to go out and buy the game from a shop or use Steam if it is available.

Because it quicker to mount/dismount an ISO than it is to search through a library of 100's of CD's/DVD's. I used to make ISO's out of all my software just for this reason. Unfortunately as others have said, some forms of DRM will not let you use a virtual drive in place of a physical drive.  

first, i bought the game. its GRAW. copy protection is SecuROM. running from a virtual drive is great, b/c if you scratch the disc, you are out a game. That sucks. it preserves the original disc so I can play the game I bought. I like the idea about installing off the iso. I wouldn't know how to check the registry, although an idea along those lines occurred to me. alcohol has a SecuROM setting. I may have misused it the first time. should i burn iso with that SecuROM option checked? I'll try that if playing with the settings doesn't work. or I'll install from iso.

Sorry, although I know of alcohol, I've never used it. I guess your best bet is to just try it and see if it works.

latest update: GRAW runs SecuROM 7.24.0009. I got that from running protection ID. selected SecuROM on Alcohol program, burned image. Then I used Acid 'drive cloaking device' and I got really close. It started to go- was reading the image- then it asked for an orig. disc, not a copy. So basically it would work if the image was created better, or something. I might try Daemon-tools, b/c it seems to be the other main program used, but at a certain point, it needs to work or I cut my losses. I've seen other posts that combine Daemon Tools with YASU with success.... I am not excited about masking drives and whatnot, seems like you can mess up a system doing that.

If it's the drive letter that's creating the problem (quite likely, it is), then you could temporarily change drive letters for the drives involved using windows' disc management tool. It's quite cumbersome, as you'll need to change drive letters twice each time you play the game, before and after playing, but it should work. Why bother with iso's in the first place, btw? Just try game jackal.

http://www.slysoft.com/en/gamejackal.html