Whenever I run the following code:
#counts length of a string .data .data string: .asciiz \"Hello\" printedMessage: .asciiz \"The length of the string: \"
Not entirely sure what you mean by fix print out, but one problem is that your count register in the strlen function is $t0 while your second syscall in print: is called with argument $t1
$t0
print:
$t1
Changing that $t1 to $t0 and running it gives output 5.