Software Update Problem and Apps Failing to Launch

Question

Ok, so, I have done a lot of hunting around to resolve this problem, (possibly problems) and tried some of the few fixes I have found, (though all were not exactly describing my problem). Said fixes were mentioned on here and on other sites/forums. Apologies if my post is described and resolved elsewhere. I couldn't find it.
Firstly, my spec:
27" iMac
Lions OSX (10.7)
3.1 Ghz Intel Core i5
16GB 1333 MHz DDR3 (installed by myself after purchase)
(Let me know if you need to know more to understand my computer further)
This computer is absolutely brand new. All I have done so far is the initial set up and installed Google Chrome and various Adobe software (CS5). Also, I did encounter a Java Runtime error and I appear to have fixed this issue by manually downloading the latest Java software.
I noticed a problem quite early on when apps were failing to launch/crashing. Frustratingly this isn't black and white. All apps, (both Apple software and third party software (mentioned above)) seem to do a random combination of:
+ Failing to launch - icon bounce a few times and then nothing (no error/dialog box)
+ Crashing - Instantly crashing when opened (typical crash dialog box)
+ Closing down - Open for no more than 5 seconds and then completely closing down (no error/dialog box)
+ Opening fine - An application that was doing one of the above three, but now (for what ever reason) working fine
For more clarity (though this isn't a rule), this is what each individual software (currently) does that I have tested:
Mail - Crashing, but now opening fine
Chrome - Crashing, but now opening fine
Facetime, Address Book, iCal - Opening fine
Photoshop - Opening fine, (though I have yet to click around and do anything substantial. Basically it appears to stay open)
Illustrator - Failing to launch
Dreamweaver - Crashing
iTunes, iPhoto - Closing down
But, like I say, this hasn't been consistent, (for example, Chrome has gone through a process of not working, working, not working and now working).
To maybe resolve this I have tried to Software Update. It finds various updates and I download them. Download seems fine, but after clicking restart to install said updates, only a second in and an error dialog box appears stating that the update files may be corrupt. It then just restarts without updating.
First idea (prompted by a pre-existing forum thread), was to delete files found in Library > Caches. After doing this and restarting, nothing appeared to be fixed/resolved.
Second idea (again, prompted by a pre-existing forum thread), was to repair disk permissions in Disk Utility. After doing this and restarting nothing appeared to be fixed/resolved.
Any ideas?

Answer 1

AppleCare's Express Lane. Do note that if you're within 50 miles (80 KM) of an Apple repair station, you're eligible for onsite repair since yours is a desktop machine.