Simply go to network connection right click go to property and select the internet protocol(TCP/IP) click property then click use the following IP Address and enter the first ISP connection like
IP Address : 192.168.1.77
Subnet mask :- 255.255.255.0
Getway :- 192.168.1.1
preferred DNS server :- Mantion here your first ISP DSN
alternativeDNS server :- Mantion here your first ISP DSN
now if you want to insert another ISP IP's in your PC
then click on Advance
go to
IP Setting
click on ADD
mantion the System IP like
IP 192.168.2.77
Subnetmask : 255.255.255.0
getway 192.168.2.77
and insert the DNS which give u by second ISP