vxd files

I have a client who scrambled windows 98 on his gateway solo 2500 laptop. I reinstalled windows, but it still can’t find two vxd files. One is fsd.vxd, the other is tsiusb.vxd. To be perfectly honest, I don’t really know what hardware these filesare referring to. Any suggestions on where to look for them, what they might do? I assume the tsiusb is for the usb port. Because, the os wasn’t working when he brought it to me, I am really working blind on what should be there and what shouldn’t. Thanks for the help.