You should be able to import the file using regedit.

Another method is to simply click on a .reg file.
The file should be a text file and have a heading with a version.
For example here is a file that turns off the low disk warning.
Code:
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Policies\\Explorer]
"NoLowDiskSpaceChecks"=dword:00000001

[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows Search\\Gathering Manager]
"BackOffLowDiskThresholdMB"=dword:00000000

[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows Search\\Gather]
"LowDiskMinimumMBytes"=dword:00000000