Windows 7 can ping but can't see device on other subnet

I have 2 Windows 7 on 2 different subnets but 1 of them is unable to reach a NAS. The topology is as follow. Any idea why this is the case? Is there some Windows settings I need to apply?

Subnet 1
- PC 1
- NAS

Subnet 2
- PC 2

PC 1 is able to do the following:
- Load the admin page on the browser.
- Show the NAS under Windows Explorer -> Network.
- Access the NAS when typed in \\ in Windows Explorer.

PC 2 is unable to do any of the above 3. It can however ping the NAS and get a response.