Psp 2000 intermittently display quit game (Home Button)

That is a possibility however there are two other things you can check:

The UMD Sensor which is a white tab that sits in the middle of the UMD drive and the UMD Door Sensor which is in the top left corner of the Bay (hold the PSP with the back facing you). It looks like a small black joystick. If one of these two sensors are not triggered then sometimes the PSP will stop reading the UMD and ask to quit.

Here is another place to look at too:

The UMD Door itself you will notice 4 metal tabs that sit on the inside. Over time these tabs seem to flatten themselves against the UMD door, what you should do is bend them away from the door using tweezers but do not bend them too much. Probably no more than 30 degrees, also becareful you don't touch the UMD drive components when doing this.