Error when windows start up

When windows starts the following error occoured

“Windows could notstart because the following file is missing or corrupt: \Windows\System32\ Drivers\Isapnp.sys”


This is another one of those messages that points directly to the culprit.ISAPNP.SYS is a device driver WinXP needs to
function properly. The message is telling you this file is either missing or damaged. Most WinXP files with a *.SYS extension are Windows device drivers that reside in the C:\WINDOWS\SYSTEM32\DRIVERS folder.This folder is one of the most important inyour entire hard drive. If any of these files go AWOL or are damaged, WinXP will report
serious errors and you won’t be able to get your system started until you restore a functional device driver.

SOLUTION

Start the Recovery Console (we’ve already discussed how to start the WinXP Recovery Console). If the ISAPNP.SYS file is still in your C:\WINDOWS\SYSTEM32\DRIVERS folder, the driver is corrupt. Rename the existing file and copy a new version from your WinXP installation CD. If the file is missing, then all you need to do is copy the file from your WinXP CD
to the C:\WINDOWS\SYSTEM32\DRIVERS folder by typing the expand command: expand [CD drive letter]:\i386\isapnp.sy_ C:\windows\system32\drivers\isapnp.sys.