I already have neoscene and uninstalled it to try out Neoscene HD. However, while installing it my McAffe anti-virus said it had a trojan and blocked it. Has anyone else had this problem

There is no trojan. Sometimes anti-virus tools get upsetting over the way the quicktime codec is protected, they think it is odd and generate a false positive.

Thanks Dave, but what do I do?

I guess disable McAffe for the install.

Well, I disabled it and now it downloads but it just won't work and then crashes.

Sounds like your PC has issues, as crashes you should not see. Submit a trouble ticket here Support Center (http://supportcenteronline.com/ics/support/default.asp?deptID=614)

I can assure you my PC has no issues. It is a couple of months old and has performed flawlessly until I tried Neoscene HD. It works perfectly with Neoscene just not Firstlight. I sent in a ticket BTW, Thanks!

First Light is not part of NeoScene, only Neo HD/4K or 3D, don't mix versions as that can be a problem. If you a very new PC, you maybe missing some DLL components, that what I meant by issues. If you where using Neo HD, trying running First Light as Administrator, once normally does the trick, although this isn't to fix a crash but some Windows 7 systems have permissions issues.