More derailleur issues, can you help me out?

Make sure your shifter cable is loose when it's in the smallest gear on the rear. If the cable is tight when the shifter is at 7 and its in gear 6 check the seating of the shift cable. Make sure you didn't bend the derailleur.

if you went riding in the mud just make sure you hose the bike down and re-lube the chain and cogs. first thing to do is check the hanger isnt bent, the hanger is the part that connects the frame to the derailuer and is ussually the moot common issue. you can tell this by putting ur bike into a gear and then looking straight on at the back of the bike, look at the deraileur where it connects to the frame, is it bent? if not then heres what you do. ohk ill give u a explanation to fix it first of all make sure your barrel adjusters are completely loose, that is that they are turned down as far as possible. the barrel adjuster is at the end of the cable where it enters your shifter, or its where the cable enters into the deraileur.there tiny things that twist. if you dont have them or cant find them dont worry about them. first put you bike in its highest gear (7th) then undo the gear cable. now check you limit of the deraileur by pushing it up and down, the deraileur should be be in line with you last gear and when pushed up should line up with you first gear, if they dont line up adjust the limit screws.they are located on the deraileur and there is a high and low screw the high dose the high gears and low does low. now tighten and loosen them until they line up, make sure you push the deraileur checking it so you dont over tighten or loosen the screws, if you do over tighten or loosen them the chain will drop of the cogs when shifting to the lowest and highest gear. once you have it in line with the gears do the following. now pull the cable just so it has tension, not tight and dont leave it loose just pull with tension then tighten it back up. now go shift through the gears. now if you cable if too loose it wont go to your low gears (1) if it is too tight it wont go to you highest gear (7) if this is the case undo tighten or loosen the cable a little bit and then repeat until it goes to all your gears. it wont be perfect at this point. now this is where you use the barrel adjusters, barrel adjusters tighten and loosen the cable by small amounts, its used for fine adjustments, now go through the gears and if the chain jumps or takes a while to get onto a gear then tighten it or loosen it as needed with the barrel adjuster remember if it doesnt go to low gears its too loose, if it doesnt goto high gears its too tight. the reason you shifters dont go into first is becasue you bike is already in first gear and the derailuer cant shift over anymore, once you fix the gears it should shift fine. if this doesnt work then take it to the local bike shop Not sure when you got the bike but if the above doesnt work then you might need NEW PARTS hope this helps:]