I Download blender 2.44 and i installed it…when i try to open this error appears:
the reading is in portuguese but basically it says that it cant find the MSVCR71.dll file.
What can i do?
You may need to update your operating system. Try installing http://www.microsoft.com/downloads/details.aspx?familyid=32BC1BEE-A3F9-4C13-9C99-220B62A191EE&displaylang=en . There’s a note about this on Blender download page at http://www.blender.org/download/get-blender/ . An alternative would be to seek that specific dll file (just google it) and put it to blender folder. After that it might work.
Yep, BeBraw is right, this is a common “problem” - either search that .dll on the net or just search it on your system - it should be there already, then simply copy it into the correct (Blender’s) folder - just in case you don’t trust some online sources 
That file should be a part of a proper Python install. You might need to re-install Python. But, simply downloading that file will work, too. However, you might have other Python issues as well.
I had this problem at work.
I simply look for the missing DLL in “google”, and download them.
After I copy them to my Windows/system32
and all was ok.
check this out… hope it helps
http://blenderartists.org/forum/showthread.php?t=102102&highlight=msvcr71.dll