Network expert needed: bizarre problem

Let me first explain the setup we have and then explain the problem. In my apartment, we have ADSL through BellSouth, with only one dynamic IP available. It came with an internal modem, which is installed in one machine that can access everything (Net, games, gnutella) fine. This host has a 3Com905B-TX network card, which is networked to the client through a crossover cable. The client has a Netsurf GFC2206 network card. Both machines are running WIN98 (1st edition) with the latest drivers for net cards.Installed on both machines are TCP/IP, IPX/SPX, Client for MS network, and MS file and print sharing. The host also has NDISWAN bound to the DSL card. (they also both have a dial-up adaptor present: is this necessary?)
So, here is the problem. Upon boot-up, each machine can see itself and the other in Network neighborhhood (NN) and access all drives. I have tried Proxy+, PPPshar, All Aboard, and Sygate for connection sharing. They all have worked, for a little while (see below.) (The proxies are OK, but I prefer to use the NAT programs since they allow stuff like gnutella, etc, from the client.)
Anyway, what happens (and this has happened with all the above programs I believe) is that after some random amount of time of even basic web use on the client, the connection to the client dies. AFTER the connection dies, the client can see itself and the host but no longer access the host harddrive in NN. The host cannot see anyone (including itself) in NN. It is also no longer possible to ping either computer (which it is before a lockup.) I have set up both computers with static IPs. The client has its gateway and DNS server set to be the host (for Sygate-different if other programs recommend different gateway/DNS.)
Rebooting the host solves the problem with Net sharing and NN, that is until the lockup randomly occurs again. aarrgggg...

So, what the hell is going on?? The diagnostic programs for both cards seem to work OK. I have set the MaxMTU for both machines to 1462 (which solves possible problems with BellSouth PPPoE implementation.) I have spent a week working on this, researching, etc, but I am finally at a total loss. Seems to be some kind of network instability, either the cards don't like each other or the crossover cable wasn't a good idea (although it was nice & cheap But what do you think?
<b>Please Help!!!</b> My roommate (on the client machine) is starting to get pissed..hehe, he wants DSL too

No IRQ conflicts. The DSL modem and both network cards are all on their own IRQs. The "modem" is not a modem as such, but just called "dial-up adaptor." Is this the dial-up networking device for WIN? because the DSL uses windows dial-up to establish connection.
Any ideas or ecxperience with crossover cables not being ideal or conflicts between different network card types would be appreciated.

Thanks

Thanks for the replys, you seem to be the only one
It seems to be an issue with our internal network. The reason we went with a crossover is b/c the DSL modem BellSouth gave us is internal; what difference would there be between a crossover cable and hooking the two PCs together with a hub? Seems to be effectively the same thing to me....

Do you know of any programs that can help test the stability/reliability of the network? Ive looked around but couldn't find any basic ones-a lot are targeted at "enterprise" type networks (and are expensive too
Would just transferring some huge files do this? I'm sure there is something better than that...

Thanks

I tried to do a search for you here but didn't want to do the log in thing. Did you search this knowledge database?

<A HREF="http:// knowledgebase.3com.com/division/publisher.asp?product=nic " target="_new">http:// knowledgebase.3com.com/division/publisher.asp?product=nic </A>


Catheter and Caffeine IV are in place. Let's PLAY.<P ID="edit"><FONT SIZE=-1><EM>Edited by Flyboy on 07/16/01 09:33 PM.</EM></FONT></P>