Have a older iMac ( 20 inch 2008). Checking to see if it is capable of running Lion. Cant find the version of OS that I have on it right now. The About Mac states that it is presently running Mac OS X Version 10.5.8. Is this version of OS good enough to be able to upgrade to Lion??? Processor is 2.4 GHZ Core 2 Duo and has 4 Gig of memory.