First, putting two cans of refrigerant in means that the system was extremely low, or is now seriously overcharged.
Does the compressor engage? Could be you had a serious leak, and whatever you put in is now gone. There is a low pressure cut-out that prevents the compressor from engaging whenever the low-side pressure drops below about 25 psi. Or you could have a compressor or clutch failure.
If the system was completely empty, it could have absorbed moisture that is now freezing.
Did you put the right refrigerant in? Not sure what year the conversion from R12 to R134 occured, but was thinking it was around '95-'96. If you don't have an A/C license, you're not able to legally purchase R12 anymore.
At any rate - for starters, need to verify the compressor operation, and put a set of low- and high-side gauges on to see where the system currently stands. With the information you've given - everything is guesswork.
As always - if you don't know what you're doing with A/C systems - suggest you will be better off having the system professionally serviced. The high pressures and low temperatures involved can cause serious equipment damage or personal injury, both of whose costs will exceed the benefits of doing it yourself.
