dorkus,

I agree with Technical. It may be time to reformat and start over.

“Splash cannot execute the following program” simply means that Avast cannot “connect” to the application from where you are trying.
The error code 0x0000001 is not really a code but a memory location.

I doubt if the problem is with Avast but more likely a corrupted Windows operating system file since you state you can access and run Avast from the file directly. My guess would be a Kernel file. You can try to download and install a new one from Microsoft (but a reformat is just as easy and covers ALL the OS files).

Norton is not easy to remove and sometimes does not cause problems until it butts heads with a program like Avast.
AVG usually (once uninstalled) does not cause problems.

I believe that Technical had put together detailed Norton removal instructions sometime back. You can try to search for the info, or ask Technical, should you not want to reformat right away.

“When all else fails, reformat!” as I always say.

Good luck
techie