These characters can be deleted using ":%s/.$//g" command from VI prompt.
To replace character use it like ":%s/.$/replace/g"
But before doing all this do ":set ff=dos", to change file format to DOS.
At last a simple trick for Gvim on Windows XP:
:%s/\r/\r/g
This replaces unix carriage return by windows CRLF.
following is the list of Ctrl characters:
Hex Name
0x00 NUL
0x01 SOH, Control-A
0x02 STX, Control-B
0x03 ETX, Control-C
0x04 EOT, Control-D
0x05 ENQ, Control-E
0x06 ACK, Control-F
0x07 BEL, Control-G
0x08 BS, backspace, Control-H
0x09 HT, tab, Control-I
0x0a LF, line feed, newline, Control-J
0x0b VT, Control-K
0x0c FF, form feed, NP, Control-L
0x0d CR, carriage return, Control-M
0x0e SO, Control-N
0x0f SI, Control-O
0x10 DLE, Control-P
0x11 DC1, XON, Control-Q
0x12 DC2, Control-R
0x13 DC3, XOFF, Control-S
0x14 DC4, Control-T
0x15 NAK, Control-U
0x16 SYN, Control-V
0x17 ETB, Control-W
0x18 CAN, Control-X
0x19 EM, Control-Y
0x1a SUB, Control-Z