Laser Collimator producing oval not circle on the Primary I own an orion laser collimator which I had not used in a very long time. I decided to collimate an old Celestron NextStar 114 and I realized that the laser did not produce a circle but an oval.
Apparently the telescope is roughly collimated using a collimation cap. 
There seems to be a corrector less in the focuser which I don't dare to disassemble. Could this oval be produced by this corrector or perhaps the laser collimator needs collimation too or maybe there is a problem in the secondary mirror?
First of all, what do stars look like through the scope, particular just inside and outside focus?  If they are oval, then read on.

I'm not familiar with this telescope, but I suspect the most likely sources of the problem are
1. The corrector lens you mention (which is a relatively unusual thing to have) is distorted.  If you can't remove this, then you are stuck with it.
2. The adjustment screws on the secondary mirror may be too tight, thereby distorting the shape of the .  Try loosening each screw by a small amount, say 1/8th of a turn, and see if this improves things.  Make sure the telescope tube is horizontal when you do this in case the secondary slips off its mount.