Okay, that's quite different than the current version of Sins.  I hope someone else can corroborate what I'm telling you, because my experience here is limited.

There was a bug in that version that caused the illuminator to have capital-type damage, rather than anti-medium.  As a result, Advent lacked a hard counter to light frigates, but could really smack around your capital ships with illuminators.  Almost all TEC capital ships were bugged or underpowered in 1.00 anyways, so you if you're going TEC you probably don't need to bother bringing one to the fight.

TEC probably is your best pick, and there are three units in particular you should focus on:  the Hoshiko, the Javelis LRM, and the Krosov Siege Frigate.  In the original version of the game, the Krosov was cheaper, tougher, and more deadly than it is now.  Combined with generally slow frigates and inferior strike craft capabilities in those days, they were regarded as obscenely overpowered.  Use them to harass the enemy's flank.  If your enemy tries the same thing on you, build a force of scouts to hunt them down.  Scouts are one of the few units with the speed to chase down 1.00 siege frigates and are cheap enough that you can build a whole bunch cheaply.

For your military muscle, use the long range frigate, the Javelis LRM.  This guy packs a ridiculously hard punch in 1.00.  Combine with the hoshiko for mobile healing and you've got a tough and vicious pack of units to search and destroy the enemy.  Avoid carriers, and eventually work towards heavies, and you should be in great shape.

Although it was before my time, my understanding was that in 1.00 Advent was considered a very weak faction.  The opposite is true now.

Well, I got paid yesterday, so I'm probably getting Entrenchment soon. I just haven't bothered to register yet. Since I've only been playing SP so far, I saw no reason to upgrade.

From bug fixes and countless little improvements, new game options, and not to mention improved game balance, patching is well worth your time.

DEFINITELY want to upgrade to the most current version. To do that you'll need impulse, which is available at Stardock.com (dont worry its not DRM, but a distribution platform). Once you have both you and your friends games updated, tips you find on the forums will be much more relevant. Its been a long time since any of us have played v1, and the game balance is much different now than it was then. 

That aside, heres some tips for taking on Advent as TEC:

Advents bread and butter unit is the illuminator, their long ranged frigate. It is the best in the game and is quite formidable. To take on a fleet of these you can do several things. You can try firing back with your own lrfs, but you'll need around 25% more ships than he has in order to win. Hoshikos will help tremendously in any engagement. You can also try carriers with fighters,but that requires a bit of micromanagement since you'll need to tell the fighters to all fire on the same targets. You can queue up targets by holding shift and clicking on enemy ships. Eventually you'll want a well rounded fleet with Carriers, Flak, LRFs, Hoshikos, Cielos, Light Frigates and Heavy Cruisers. But until then make sure you're constantly scouting your opponent to find out what he has so you can build the counter unit, or make sure your fleet is bigger. NOTE- Do not under any circumstances engage illuminators with light frigates, because the illuminators will rip light frigates to shreds if that is all they're firing on. Also, Illuminators have 3 guns that fire in front and to each side, to absorb some of the damage they deal, bring some flak in with your fleet to take some of the hits from the illuminators side beams. Flak have much thicker hulls than your LRFs and can take the punishment, helping to keep your fragile lrfs alive so they can dish out their missiles.

All right, I'll be patching as soon as I can find the cursed manual. Thanks for the help everyone.

Me too.

-Exile Ascendant