Hello , I changed lap top and I encountered these problems..?

A- I cannot get  computer authorized to use Adobe,( after a few trials  the damn program opened) but

B- My device is not accepted

then it was recognized

so I bought two boooks from my usual suplier:  www.ebooks.com and when I tried to copy the books on my reader I got this message: error not authorized.

So I tried to install Adobe again  this time the books were coped but when I tried to open them ( not at the sa,e time) I got error on my e reader.

My e reader is a Trekstor Pyrus and before changinf my computer I never had any problem ,

Is there someody who can help me before I go crazy a?

Thank you in advance.