DSL: bad conection+unstable system

Hi i just recently got an ethernet card and upgraded to DSL. Something about my connection is wrong and my system has become very unstable:

I installed the ethernet card, then on booting the pc asked for my win98 cd for some drivers, then for the disk that came with the card, then i installed the "acess manager" software that came with my ISP's instalation kit.

Connection problem: When i access the internet i get a message in the connection window that says "cannot find gateway" but it manages to connect anyway. I know something is wrong because the little icon in the system stray that represents the modem has one yellow screen and one green screen, instead of two green screens. It's the top screen that's yellow.

My ISP's crappy suport team said that that isn't normal but that if i can connect i shouldn't worry about it. so they're not helping.

I know somehting is wrong with my connection because i get oddly long pauses before the page connects and loads...even though it loads very quickly once it does connect.

Also , Outlook and IE. 6 keep thinking i'm OFFline and ask me to connect , with the old dial-up window , i just click on "ignore" or "try again" and then it falls back on the dsl connection. Firefox has no prbs.

Instability problem: Once i got a "WINDOWS DEVICE IOS error" on boot up. But then re-booted in safe mode, de-fragged, rebooted normally and the problem went away. AND once on boot up i got a message: "HARDWARE MONITOR found an error. Enter Power Setup menu for Details" and ended in up in some crazy thing called "AWARD Bios SETUP UTILITY". i just exited and rebooted and it resolved itself. I've also gotten a few blue screens on boot-up.

But usually i just boot-up use the high-speed, and the system get unstable after about a day of use , before needing to be re-booted, usually after a freeze.

I also recently upgraded my RAM if that might be related.

Any ideas? Is this the right forum for this even? Is it more of a driver or software issue?