How to erase junk Chars coming in only the first line

I have a file containing few thousands of lines. when I do cat on it , i find it having two special Chars at the start of first line alone as shown down here.

��HDR|20111024|01      

If i delete this line and do a cat on file , the current first line is shown to have the same special Chars.

��Obs,PIN,registerNum,txnNum,DateVisited,StoreNum,MetricDate

And For clarity of understanding the Issue , the file is indicating to have been converted and saved when :w command issued in there.

"EDW.VOC.BK.FEED.SEQ01.POS.txt" [converted] 113682L, 7194355C

I want to know how to get rid of the special chars and whether the issue is due to file not being converted properly as it was Ftped from Windows before being converted using :set ff=unix .

Please help me with getting over it.

Thanks.
Subbu.

Can you attach a file with an example? With only one row?

What are the actual characters? ( od -x -N32 infile )

sample file is attached with one line that is having special chars at the bginning when Cat is done on it in unix.