360 issues (Disc drive/clock)

Hi, I am having issues that I think relate to my 360's disc drive - several games are suffering from frame rate and freezing issues:

• Burnout Revenge (the worst culprit - loading times slow down/screens become sluggish when retrying events, the frame rate sometimes slows down and there are various judder issues in Crash mode - in addition, the game froze completely at one point, necessitating a console reboot)
• Dead Rising 2 (mainly in busy areas where there is a lot going on - at one point the frame rate jolted to a standstill - and possibly some screen tear as well)
• GTA III/Vice City (again, severe frame rate drops whilst driving - I already turned trails off - though I understand, with Vice City at least, that this is a fairly common issue).

Also, the internal clock keeps resetting itself to 12:00 on 22 Nov 2005 each time I switch the console on, despite having changed it numerous times. Could anyone please tell me what the problem is? Thanks.

ETA: If it helps, my console is a 360 Arcade from, I think, late 2009.

UPDATE: I took the hard drive off, to see whether that would remedy anything, but I am still encountering the same problems; Burnout Revenge is even more sluggish, and Dead Rising 2 won't even work without the hard drive (although I suspect that this may be to do with the fact that I installed the disc).

As said above, I suspect the problems lie with the disc drive. Any advice/help would, of course, be greatly appreciated. Thanks.