Win98 network problems

Hey,
I've got a weird problem with my Win98. I just got an internal ADSL modem and I installed it in my computer. But I had a problem installing the driver: after installing the files from the driver cd, the program asked for some files from the Win98 cd. It copied some of them, but just at the end my computer crashed. After rebooting, everything worked more or less ok, but I got an error message at startup, saying that the file CAPI2032.DLL couldn't be started.

I uninstalled the driver and tried again a few times, but always got the same result. After messing with it for 3 days (which included a bunch of serious problems and 4 re-installs of Win98) I gave up and took the ADSL modem out. Now my computer works more or less fine, except for one thing.

Since the ADSL didn't work, I installed my old Well 1414 ISA modem just to get online for a while. Everything seemed to work fine: the computer found it and it responds the way it's supposed to. I can even connect to my ISP. But when I try to run IE, it crashes with an illegal operation. And I get the same thing with Netscape, ICQ, mIRC... you name it. And these programs crash the same way even when I'm not connected to my ISP: in fact, IE is the only program that can actually bring up the dial-up networking screen. All the other programs crash when they're supposed to use the internet connection for something.

I've ran diagnosis programs and all that, but they all say that nothing's wrong. Yet something MUST be wrong since I'm unable to use internet for anything. Another re-install of Win98 didn't help.

Any help is appreciated.