Help, my first Apple product. Is this normal or did I make a mistake?

Question

Hi I just bought my first ever Apple product ever.  New to me is an old 17 inch iMac (late 2006 build) that according to the serial number was actually assembled in May 2007.  Anyways I hear how Macs never crash....  I bought this on EBAY with only a guarantee not to be dead on arrival.  Appearance wise this thing looks new.  It came with 10.7.0 installed.  I ran this for a few hours no problem.  It asked me to update so I did.  During the update to 10.7.5 the process was going slow so I walked away.  When I came back the screen was dark and the light on the front was on solid.  The system would not respond to the mouse or any keys.  I held the power button and it shut off eventually.  I started it back up again with no problems and spent a few more hours on it.  Then I decided to look at the serial number to find out what I actually got.  I had it turned on when I gently laid it back to see the number on the stand.  When I tilted it forward back onto the stand the screen was frozen.  It is possible my big belly hit some keys when I did this.  The brightness logo was on the screen along with the web page I had up.  However the mouse or keyboard did not do anything.  I see these had a high rate of logic board failures and I am worried about that.  I repowered again with no issues yet. (about two more hours)
So what I want to know is if this is normal or not.  A windows machine freezing during an update I would not think twice about it.  I also have no idea if it has a safety that would be triggered by laying it back?  Would the system ignore the mouse or keyboard if my big belly rested on it thinking it had stuck keys or something?  Your ideas and thoughts please.  I only need this computer for in the kitchen use and also to retrieve old videos from a even older camcorder.  However I do not want to waste money on something that is broke.    Thank You.

Answer 1

Thanks everybody.  It looks to me that the seller gets these in bulk from either schools, libraries that are updating equipment or something.  That would explain the no discs.  He sells a lot of them.  It is very clean, taking the access cover off no dust or anything.  Appearance wise not a mark on it except for some residue from tape that I was able to clean off.  It looks showroom condition, not faded or anything.   I paid only $130.00 for it.  For another $47 I can get a two year warranty for it.  I guess that is what I will do since they are dumb enough to offer such a warranty on a old computer.
I will take the advice and buy retail of Snow Leopard.  I was thinking it may be a better choice for me anyways for what I want it to do.  Look up and store recipes, play music over bluetooth, perhaps watch a video.  I also bought it for the old firewire port that I need for my 15 year old camcorder before that stops working or the tapes go bad.  I see the new ones have Thunderbolt ports that I would need to adapt to Firewire 800 then to 400 and again down to the small 4 pin port for the cam.... and hope it works on an old cam.
Anyways curiosity got the best of me so that is why I dipped my foot into an Apple.  I did not want to blow a grand to find out if I like it or not.  With some other upgrades, larger hard drive, one more GB of memory, wireless mouse, keyboard, Snow Leopard, and the extended warranty I will have about $250 invested in it total.  I would be happy if that gets me through two years of mundane use.  Perhaps I will be hooked along the way....