I think you need to specify the disc name, it's missing in your directory. For example "D:/Users/Rahul/Desktop/Dfiles/106_2015_34-76357.pdf". I tried and I can read without any problem.
Or if you want to find the file path using the os module which you didn't really associate with your directory, you can try the following:
from PyPDF2 import PdfFileReader
import os
def find(name, path):
for root, dirs, files in os.walk(path):
if name in files:
return os.path.join(root, name)
directory = find('106_2015_34-76357.pdf', 'D:/Users/Rahul/Desktop/Dfiles/')
f = open(directory, 'rb')
reader = PdfFileReader(f)
contents = reader.getPage(0).extractText().split('\n')
f.close()
print(contents)
The find function can be found in Nadia Alramli's answer here Find a file in python