If you ever run into an issue with a down VPS, and are unable to restart it with the following error:

Failed to start Virtual Private Server '21656'. System error 1:
Virtuozzo API function call 'VzkrnlStartVps' failed dwErr = 0x000004FB   (or something similar)

This generally means the vps was updated using windows updater, which is fine if this was a dedicated server. However since this is a vps account, you can only install approved patches from Swsoft/Parallels (http://www.parallels.com)

So, in order to fix this, log into the host node, open a command prompt, and perform the following:

copy c:\WINDOWS\system32\drivers\tcpip.sys c:\vz\privte\$\root\c\WINDOWS\system32\drivers\

If this file differs from the host node, the vps simply cannot start, and the above just replaces what was patched/replaced with what the node is using.

Once you have done this, you will also want to assimilate the vps by running the following command;

Vzfsctl assimilate VEID (their vps ID).

Once you run this, you will be able to start the vps up and have it running again.

* If this does not work, go back and copy the entire driver directory from the Windows directory to the VEID’s \Windows\system32\ directory. *

:)