laguna alize 1.9dti x reg 2000 timing marks?

hi ya my auxillary belt frayed into small bits but there was about half an inch of the belt left ,started making a noise with the belt being whipped around,put new auxillary belt on and the car now sounds alot louder ,will not go above 30-35 mph and will only go upto 2000 revs,also a two symbols have come on the dashboard.one is a small box with 3 squiggles through it and the other is SERVE,if youve got any idea what it could possibly be what damage i have done i would be very grateful thankyou.also i have checked timing marks to my manual and i cant see a cut out bit on the camshaft mines got a round dot ,is this the same