I agree the vertical lines are possibly caused by the video card - I had a similar problem a while back. The problem was worse when using more complicated Win95 screen displays as they are more memory intensive. I got my card fixed under warranty, I was told it was a failing on-board memory chip. (The dealer tested it while I waited and got the same problem in Windows 95). The rest of your problems are most likely caused by DMA / IRQ conflicts involving your new SCSI board. Some sound cards are fussy about which resources they use so it's best if you don't mess with those. If you have the original driver software for your video and sound cards, try re-installing them. Good luck!
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May the Force be with you - and may Gravity treat you gently..