Sounds like a bit more than perhaps we can help with in one hit.
The screen problem you mention sounds like a poorly attached cable or the video card is lose in the slot (ie a hardware prob)
The rest sound a lot like software/driver/irq/memory conflicts which are probably best fixed with the usual windows style, Backup, re-install.
With your memory not behaving depending on you Motherboard type you may not be able to have a 16M module next to a 64M module, or the MB may not even support SIMMS that big (My old MB was limited like this) Dig out the manual that came with the MB and see what it says, you may also have to put the memory in a specific order for it to co-operate.
Hope this helps some.
PS. There are some excellent guides out there that can help with re-installing Windows. A search of somewhere like
www.metacrawler.com for "reinstall windows" should yield some results.
www.worldowindows.com is another handy place, esp. for drivers
[This message has been edited by OzmateBugsmasher (edited 25 October 1999).]