Mac Book Pro doesn't boot (twice; after updating) and slow performance before these incidents

Question

Hi,
Maybe someone can help me resolving a (re) boot issue with my Mac Book Pro. Last few weeks I experienced a tremendous drop in performance (start-up as well as handling and using applications).
Yesterday I downloaded and installed  an app to clean stuff from the mac, such as binaries that aren't used, cache files, etc. It resulted in substantial better performance. Than, I used the updater on this application to update. This morning, the Mac wouldn't boot. After several attempts I used the old DVD with Mac OS X to re-install and boot. That worked.
Following this approach, I received two messages (that HP apps weren't secured or something and therefor disabled). Than I updated the Mac OS X and later this evening it asked me if I wanted to install some (4) other updates as well (don't know what updates these were). So I updated but now I am back at square one: My Mac doesn't boot. I do get the grey starting screen, but now even the 'apple' logo is missing.
Anyone else experiencing these problems and have any clues on how to fix it? By the way, I also tried to alter permissions on all files on the main hard drives (to ensure that I do not always have to sign off on updates and or changes of applications). Would that have caused problems?

Answer 1

You seem to have a lot going on here, so it's hard to know what's wrong. You likely had some underlying problems before doing the Software Update.
Here's a link that might help with the grey screen problem:
http://support.apple.com/kb/TS2570
Which app did you download?
If you can get booted up, check in the System Profiler to see that all of your RAM is recognized--if not, you may need to reseat one or both sticks.
If you can boot from your install disc, run the extended version of the Apple Hardware test to check for hardware problems. Freezing can be caused by a dying hard drive, which can also tend to corrupt software.
While booted from the install disc, navigate to Disk Utility and repair your boot disk. You can do this 2 or 3 times even if it says no problems found.
While in Disk Utility, check to see that the SMART status of your hard drive is verified. If not, you will need to replace the drive.
It probably wouldn't hurt to reinstall the OS.
Do you have a good, up to date backup? If not, it would be a good idea to make one as soon as you can, just to be on the safe side.
Have you tried a Safe Boot?
http://support.apple.com/kb/ht1455
http://support.apple.com/kb/ht1564
These are just a few ideas to get you started. Post back if you have more questions.
Good luck!