ATCG is for MS-Windows 2000 and up.
Remove numbers, white space and line feeds from the nucleotide sequence that you've just copied with one click on your computer's speed bar. Download it now.
Install ATCG and copy a shortcut of the program onto your speedbar.
As an example, copy your sequence from the ncbi nucleotide site. The clipboard then contains, besides the characters A,T,C and G, also numbers, white space and line feeds that you might like to get rid of. Just push the white circle icon once, before pasting the sequence in your text editor. ATCG removes all characters other than A,T,C and G and changes them to upper case. This is because it seems that not all sequence alignment tools like lower case.
Simpler is not possible.