Well, I've been having some 'issues' with my 360 lately... Before you ask- it's not the RROD.  It's a little more bizarre than that - some games, many in fact, won't load fully because the console says they are unreadable, implication being they are scratched or dirty.  Now I can categorically state they aren't. I've tried running lens cleaning CD's in the DVD drive - and it doesn't seem to help much.  Wierdly the other day I couldn't Gear of War 2 to load at all - I took the HDD out and re-fitted it, and it worked, but can I get Gears of War 1 to load using the same disk removing shenanigans? 
 
Nope. 
 
Has anyone else experienced this I wonder?  Is it a common problem easily fixed or am I going to have replace/repair my 360?