My Morrowind suffers from a variety of errors, including the usual crashing. One of the most annoying and dreaded errors goes as follows:

I'll be walking around in Morrowind, when strange triangles appear, stretching from the cursor to the edges of the screen. Then anything that is menu (like object titles, dialogue, the menu itself) becomes distorted, then I can't access the main menu, among other visual/control errors. Sometimes it is accompanied by having my quicksave/autosave go corrupt. Now basically my game is frozen or otherwise unplayable. A Windows dialogue box pops up with an error that looks somewhat like this example: 0x00583 (random letters, but appears similar to this example). On rare occasions the error and its symptoms spread to other programs and I am forced to shut my PC off by holding the power button.

My virus scan software detects no threats anywhere involving Morrowind. What is going on here?

That sounds like a hardware problem of some sort. If you're lucky, it's overheating...when's the last time you cleared the dust out of your computer?

I don't think its an overheating problem, I turned off my computer for a few hours and played Morrowind again, and it did several times still. But I have spotted a new side-effect to this error, I get a message saying something like, "Morrowind.esm is not a valid TES file. Continue Running Executionable?" If I press yes and not cancel, it will go on to tell me that all loaded master and plugins are invalid also. What do you think could cause this? Could it be my high amount of mods? I have 44 mods uploaded plus the official expansion packs.

it probably is. 44 plugins is a lot. my game crashes a lot with 1 plugin

If it spreads to other programs, its not a game problem. As Abramul said, a hardware problem. If you are sure it's not something overheating, Then try reseating all boards and connectors (Unplug and plug back in) - Be sure to shut off the power AND unplug it first. Clean out the deadly dustbunnies while your case is open. if you can, blow out your power supply. Look at things like an old floppy drive or PC card slot for dust accumulation. Use a soft bristle brush, something like camel hair to brush out dust. Nylon and other man made fiber brushes can generate static. Make sure all fans are working too.