memory loss

Hello all. I am not sure what has happened. Had a warning about low memory and while going to clean up the system my macpro reboot and has never been able to boot properly again. The only reason I can still do anything is that macs msn msgr tries to kick in and gives me the bar with the Apple logo. Otherwise I would just have a white screen and no response.
My recovery disk says its locked when I try to reboot from it and thats if it shows at all. I did not make a usb drive or anything and I am not positive exactly about what has happened so if anyone has suggestions or anything I would be very happy to hear them.

I have a macbook pro with OSX 10.7.5

G'day and welcome to the forums.

Think you mean lack of free hard drive space. Your drive needs a minimum of 15% free space to operate anywhere near efficiently. Memory is Read Only Memory which has nothing to do with storage space. What do you mean Recovery Disk? Lion was in the main a downloaded file and was never issued with a disc.

The hard drive may well be failing. Boot and hold down Command R immediately after the chime to see if you can get into Recovery, and if so go to Utilities in the Menu Bar, Disk Utility and run Repair Disk to see what is recorded. If all is okay you may be able to boot into Safe Mode ~ Boot holding down the shift key.

If you get in and see how much free space is available. You will need either a larger hard drive for your MBP and the current drive can be placed in an external case and kept for backups.

Yes that is what I meant. And thank you I was able to use what you said and have solved my issue. I do need a larger drive but I am good for now and can use my computer as normal. Thanks again!