UNPLUG YOUR DRYER BEFORE STARTING ANY REPAIRS
Sounds like you have two problems....
#1 problem....Your first problem sounds like drum rollers have flat spots on them or in need of lubrication, or maybe your belt has slipped off of the idler arm pulley.
If you have a front loading machine,
Remove the electrical console that holds the timer switch, start switch, etc. from the top of the dryer.
Be REAL CAREFUL not to knock any of the wires off of the timer switch. Then remove the top of the dryer.
Remove the front of the dryer. This will expose the drum and belt. Remove the drum and belt and this will expose the drum rollers, idler arm pulley and motor.
Now is a good time to check the belt to see if it has slipped off of the idler arm pulley and also check the belt condition for wear.
Be sure to note the route of the belt, this will come in handy when you go to reinstall the belt.
Check your rollers for flat spots, if they have flat spots on them replace them.
If the rollers don't have flat spots on them then they probably only need lubrication. Lubricate the shaft of the rollers with a good grade of machine oil such as 3 in One oil. Reassemble the dryer, plug back in. This should solve your noise problem.
Your second problem may be with the heating coil.
Remove the back of the machine and try to locate the air duct going from the blower to the drum. Normally inside the air duct you will find the heating coil and the thermostats/thermistor.
Once you have located the heating coil, remove the two wires from it and check the coil with an ohm meter across the two terminals of the coil.
You should read continuity across the terminals, if not then you will need to replace the coil as it is faulty.
If the heating coil is ok, then:
You can check the thermostat/thermistor by removing the two wires and taping them together with electrical tape.
If the coil heats up then replace the thermostat/thermistor.
DO NOT LEAVE THE WIRES TAPED TOGETHER AFTER THE TEST. This could cause a fire, as you have removed the safety of overheat from the machine.
I will include these two websites for parts and further help:http://www.partselect.com/http://www.appliancepartspros.com/index.aspx
Both also have chat assistance 24/7.
I hope this helps