I just reformatted and had no problem whatsoever with NS before.

I backed up the following files:
1. HL1110
2. SteamInstall_CS
3. NS Install Beta 3.0
4. NS V3.0 Beta 4 Patch
5. NS V3.0 Beta 4a Patch

I have installed HL1110 and Steam CS Install. Now when I click NS Install Beta 3.0, a box pops up and says "STEAM with proper ThirdParty mod support is not installed." I click OK and I can't proceed with the Patches because they rely on Beta 3.0.

Is there a solution to this? Am I missing a file?

Make sure befor insalling Beta 3.0 you run half-life through Steam atleast once. Once playing Half-Life through Steam atleast once Instal Beta 3.0 into your Program Files\Valve\Steam\SteamApps\e-mail\Half-Life - folder. Once you have done this all of the other patches (beta 4) and (beta 4a) will automaticly install into the same folder.

This should work if not, probally one of your files is corrupt and you'll have to redownload it.

U shouldnt use Steam with the CS cache. Use the one with the Half Life Cache. Once you install steam with the HL cache it should solve your problem.