Hi. I've been facing hell lot of problems with my MBP of late, and all that I could try have turned unfruitful. I'd appreciate some help. Problems started when I downloaded and tried to install SL update 10.6.7 on 10.6.6. It was working fine on 10.6.6. The update failed, and I received 'error code 50' very often while deleting files from Trash. Also, 'beach-balling' became more frequent, and I had to force quit applications very often because of 'low application memory' box being displayed.I also encountered the grey screen prompting me to 'press power button till shut down and restart'. Finally, I tried a clean reinstall but the same problems persisted, and lots of applications stopped working. I could not download files from browser (Low disk space, despite a 100 GB space available on he HD) or save textedit, Office or iWork files. I did a clean reinstall again, with zero-erase option and again downloaded the 10.6.7 combo update. The 'Software Update' application failed. I downloaded the update from my browser and it was installed successfully finally after 4 system restarts, but the 'error code 50' problem still persists. What am I doing wrong? I've been dealing with this abnormal performance for more than a month. I haven't backed up files because there is no use making a backup of corrupt system. Specs : MBP'09, 13.3". 2.26 GHz, 160 GM, SL 10.6.7. Please advice. Regards.