Help please..what is L1 cache..

I hope somebody who reads this can help... I have a slot A 950 with a ASUS K7V...been running for
months without a problem, Win 2K, Sp1.

Today I added a stick of 256 corsair pc-133 memory and I blue screened when I booted up. Of course I removed it and I still blue screen all the time (on boot), even with the original 128mb.

When I disable L1 cache I get further in the sense that the loader completes and the windows logo appears with the movement of the blue bar accross the bottom...but it never finishes loading, because its too slow..I'm thinking some how my motherboard got whacked. I get a blue screen even if I try re-installing. I popped all the cards except for the essential (video) and I still blue screen..whether I'm trying to boot from the disk or re-install from CD..

If anyone reading this has any ideas on what
could be causing this, or what L1 cache is, please let me knowm thanks.

David