These are just 2 of 65536 (2^16) ports to your system, all of which can be either open or closed. Some of them are reserved, others not, and by closing them explicitly, you might prevent useful software and services from working. To be 100% safe, in theory, you would need to isolate your machine from all networks (EDIT: that is, if we exclude other threats such as infected devices w/autorun, sneaky people, etc... :p)
General tips for Windows 7:
- If you are not sharing files or printers, change your network type to "public place" (this will make the Windows Firewall more restrictive (instructions can be found here)
- Keep your software updated to remove as many security holes as possible. This is REALLY important!
- Install Anti-Virus! Microsoft has a free one (Security Essentials), which I like, but Avira and AVG is nice as well (also free).