Air Conditioning - A/C won't cool

Greetings to all,
I am new at this thread and would like to ask the experts for advice on what items to check on my Air Conditioner. I have a Sears Kenmore window unit, it has approximately two years, I turned it on and air comes out but it is not cold. I set temperature to 68 degrees and checked with thermometer and received a reading of 75 degrees. AC unit is not cooling, I also saw frost on the three tubes entering the evaporator coil and frost began to form on the evaporator. Can you give me some advise on what items to check, or what could be causing AC not to cool.
Thanks
Eddy608

check to make sure the evap coil is clean. Then get some soap bubbles & check the loops up & the sides of the evap coil & condenser coil. Most window units develop freon leaks in the condenser coil in the bottom few loops where all that water tends to sit. If the soap starts to bubble * you have a leak a lot of time you can just braze the hole & recharge the unit but it is usually not cost effective to buy new coils & compressors for them.

Like said if filter and coil is clean frost on the lines . Then you have a leak. Costyou are better off to get a new unit just like it if you can. Save the fan motor , capictor and controls off it. Might fit the new one.

Thanks I check it out and keep you posted. Sears has a special at this time on these units $600.00. I'll check for leaks and if it cannot be repaired will purchase the same size unit and dismantle this one for parts.
Thanks again.
Ed.