825th_tomcat wrote:Just literally logged my sham box on and went to invite him and the same thing has happened again. He had nothing going on in any boxes apart from the usual log in text and 2 message in /ooc.

This is the most concerning aspect, since I've never crashed or disconnected outside of a zone crash or combat scenario, personally.
I can only recommend you start up your client with the *least* complexity first. Basic client, no 3rd party programs, and all combat chat filters set to OFF. This will limit the type of traffic going on between your client and the server down to the bare essentials.
Once you confirm that there are no crashes in that scenario, you may then add another layer of complexity until you reach the one that crashes you. I recommend that the first time you load up MQ2, unload all of your plugins. Then add them in one by one. It's a tedious process, but narrowing the perpetrator down is the only surefire way I know of to isolate the problem.
As for the plugins... 99% of 3rd party program crashes have, in my experience, been related to plugins swapping items around in your inventory. A plugin such as MQ2cast uses MQ2exchange to swap a 'must equip' item onto your character and then swap it back out after it's done casting. I've found that if a cast command is poorly timed with MQ2cast or spell_routines it will result in an attempt to swap an item WHILE you're casting. That's pretty much always been an instant client crash for me.
Server disconnects and de-syncs have always been related to the combat log. I'm willing to bet you're in the United States like me. Being half the world away from the server, I have to use in-game filters to limit the number of packets going back-and-forth from client to server. With enough people and enough battle spam, the packets can't (for me) seem to route fast enough to keep my client up-to-date with the fight as the server sees it and I'm disconnected.
That being said, I've reiterated a few things that Sticky said, and I think he's spot on for pretty much everything. The only part I disagree with is the graphics settings. Your frames per second should have zero bearing on your connection with the server. In fact, the worse your FPS, I'd argue you're staying even more in sync with the server since you can't do much of anything quickly!
Ultimately, I think you're disconnecting in combat due to your combat spam and out-of-combat due to MQ2exchange. Hope this long-winded response helps.