Stay away from CS4, the new CS5 is due April next year. CS4 have very serious critical bugs that Adobe wont care to fix. The problems start with its installer. Read this feedback forum: http://forums.adobe.com/thread/484224?tstart=0
In this Forum Adobe is telling us how we have been treated like dirt and so far Adobe have NOT fix the problem. Adobe just does not care.
Save your money and comeback after CS5 is released to the Feedback forum to read all about the bugs and problems that Adobe wont care to fix. Then you can decide if you want to waste your money or not.
Just trash the darn trial!
That's not gonna help if he seriously wants the product and doesn't have a previous version of AI, is it? And whether actually CS5 will be available in April, is another question entirely. At this point it's mere speculation.
Can you provide more details about your system? Any virus scanners/ security tools running? Other Adobe products already on the system? Processor? Graphics card? Available harddrive space? Have you looked into your system event viewer log and noticed any crashes/ failures of processes or services?
I think the question is why Adobe have not fix the installers?
How many years this company needs to fix something that was severely criticized right from the beginning?
Even John Nack said it in his blog : http://blogs.adobe.com/jnack/2008/12/notes_from_installer_mgmt.html#more
Or try this article dated Dec 3, 2008: http://www.macworld.com/article/137296/2008/12/adobe.html
So why waste the time installing faulty software with critical bugs that Adobe refuses to fix?
Where is CS4 update?