Run the tool PCI-Z to see which devices you have in the PC.
PCI-Z is designed for detecting unknown hardware on your Windows based
PC. It will help you determine vendor, device and certain details
about device even if you don't have drivers installed. Software uses
The PCI ID Repository, a public repository of all known ID's used in
PCI devices: ID's of vendors, devices, subsystems and device classes.
It is used in various programs (e.g. The PCI Utilities) to display
full human-readable names instead of cryptic numeric codes. It is
almost similar to lspci Linux command but with full Windows support.
Now go to the vendor homepages (relatek, broadcom, nvidia) on a second PC to get the drivers. Transfer them via USb flash drive to the PC and install the missing drivers.