I don't know what "the best" is, but you can get the ROMs from ipdb.org .

Meloyelo51 has a shop offering ROMs here on Pinside and excellent customer service.

Thanks for the referral!

Yes I can help if you need them burned...I am licensed/authorized to do Bally/Williams' games.
If you just need rom images to burn yourself you can download from planetarypinball.com or I second ipdb.org
Off the top of my head, normally I would think you would be getting checksum or boot errors if the roms went bad, but it is possible depending on the game.

You also may want to try a factory reset and check your batteries. Memory could have corruption. If you still have batteries....you SHOULD replace with NVRAM. (be sure to write down any settings/audits you don't want to lose as they will be cleared)

Before changing game and sound ROMs, start by reseating ALL connectors and ribbon cables on your CPU board and sound board one at a time to see if things change. Press on the ROM chips to make sure they are not loose in their sockets.