I'm had configured a lan with win98 pc's
I'm need integrate a pc laptop with win xp in that lan
I'm had configure network environment in the laptop so I'm can ping to laptop normally but I'm can't ping from laptop to others pc's

whats the problem ?

Configure the other pc's to network environment. Microsoft designed the os to enable or disable file/printer sharing... most likely they are still in default setting of "NO, do not share my files and printers"... change that to "YES I want to share my files/printers" by double-clicking the NETWORK icon in Control Panel and then click the FILE and PRINTER SHARING button... you can choose to share files only or share files and printers by ticking the appropriate box next to each. Then you can open Windows Explorer and right click drives, folders, files, etc. and click on Sharing in the drop down menu and have lots of ways to choose what is shared/not shared with the network. What you allow on each pc is what will be seen on the rest of the network pc's.

Note: Windows has built in NETWORKING help that's available from your START menu, HELP.... There are also dozens of internet sites with networking help, including Microsoft.com. Just use any search engine and type the following keyword: network help :)