Have you enabled printer and file sharing on your Windows machine? Also, it will have to have the same workgroup name as the Mac and visa versa.
Not sure about the IP addresses, because if your IP is via DHCP via the router, the IP should stay the same as should the gateway - only the 'true" IP changes - but the true IP is not needed to connect/file share because you are using a router.
For example, the gateway on some routers is 10.0.0.2 - therefore the IP assigned on your machines will be 10.0.0.? - replacing the ? for a number usually between 4 and 15 if you have them set automatically.
This will stay the same - but, the true IP will change - but only the router assigned IP is needed to connect if they are networked via the router. For example, to connect to my Windows I only have to type in smb://10.0.0.6.
Your router gateway sounds like the 192.168.1.1 - therfore, I am unsure what 101 is doing on the end of your address unless you have set your machine in manual range for IP via your router?
However, a common problem of not seeing the PC on the Mac is a PC firewall such as Zone alarm and/or antivirus software such as Norton. If you are running a firewall then ensure you have put the Mac’s IP address as a trusted IP into your firewall's trusted zone settings - otherwise you will have no chance of seeing it.
Also, if you have Norton AV installed, or any other AV, disable the auto-protect feature. You should then be able to ping your PC from the Mac.
As things are working the other way around (PC>Mac) I would think that it is likely to be your PC firewall/Av that is causing the issue.
