Getting a working virtual version can be a bit tricky nowadays since the games of old typically utilized CD residency. Since the virtual CD software you're using isn't properly working... there might be some anti-piracy stuff on the disc itself that your ISO creation tool failed to properly capture.
HOWEVER, there are a few tools that can be a bit more useful in this regard.
Originally, I would had recommend Game Jackal since it typically reviewed the game's call to the disc drive so it only has to grab the necessary stuff to properly run. This had the advantage of seriously decreasing the game's disc image size considerably. HOWEVER, the software has been discontinued due to some legal issues with the software & the publisher of the software (Slysoft) has shut down. The developers of the software (RedFox) has elected NOT to revive the software due to the abundance of digital distribution platforms (like Steam, Origin & uPlay).
Alcohol 120% is dual-component program that allows you to burn CD's (known as Alcohol 68%) & virtual disc drive (Alcohol 52%). Alcohol "plays nice" with anti-piracy stuff, but there's 3rd party stuff to bypass it. The Free version allows you to have 6 virtual drives at a time while the paid version allows up to 31 virtual drives.
The alternatives would be to look for a No-CD option or patch, preferably by the developers of the game (For example, Blizzard provided No-CD options for Diablo II & Diablo II: LoD for those who originally purchased the physical copy some time ago). HOWEVER, you may have to resort to more "questionable" patches. Such patches are generally considered illegal as they're released by 3rd party developers (known for cracking DRM) & may include some unwanted "extras" (like viruses or other malware that your anti-virus / anti-malware programs will likely flag).
You can also check GoG.com (previously known as "Good Old Games", but many still unofficially utilize the old name... despite the site offering more modern titles) to see if the game you're trying to play is in their game catalog. You may not like repurchasing the game, but their prices are reasonable ($6 - $12 for classics, excluding any sales), they've already done the legwork to make the game work with modern systems (with emulators like DOSBox or their own modifications) & are DRM-Free (so you don't have to deal with install limits or online activation or verification stuff, with the only exception being with games with online multiplayer services). It might be worth spending the money to eliminate headaches trying to get your original copy working.
Hope this helps!