[QUOTE=gwynevans;419076]For existing PDF, try
PDF -> MobiPocket Creator -> PRC -> Calibre
For TXT, better than going via PDF, try
a) TXT -> TXT with
Markdown syntax -> Calibre
Many thanks for your attention and understanding for me, for old wild soldier!
I have downloaded, unzipped and read "Readme Me" file from "Markdown syntax". What I could understand, this software required for this work on my PC some additional soft. I has listen somethig about Perl, but I'm not a programmer, I'm only DSNG engineer. Due to this circumstances, it's too difficult for me, install third party, never before used me software, and integrate to this Markdown. I'm so sorry.
P.S. What about PDF - (PDF<Recycle bin<empty Recycle bin) - absolutely right action! Fully agree.