I never knew routers could crash my entire PC before

But it turns out they can. A while back I posted about an issue in which my entire PC grinds to a halt, as if though all of my CPU power is suddenly drained and all I can do is a hard reboot.

So, I tried updating drivers. I tried disabling programs. I tried scanning for viruses. I tried scanning for spyware. I tried removing hardware. I tried avoiding certain applications. I tried always running other applications.

But damnation, I could NEVER find a pattern, until... I booted up with my router disabled, not even remembering clearly why but... all of a sudden, I was running smooth, no errors! Of course, it was kind of useless since, hey, I largely use my PC for connecting to the 'net.

Reconnected my router, and as soon as it had a connection to the 'net, BAM, down it went.

I've got a Sagem router, not sure of the details beyond that as the box is rather black and sparse(supplied by my ISP) and a Linksys WMP600N wifi adapter.

I know a lot of you won't believe this can happen, but a quick googling found me stories of people who actually had BSOD's and stuff just because of a weirdly incompatible router.

Any suggestions? Calling my ISP was largely fruitless.

Replacing my wifi card is obviously Solution #1, but if I could avoid that, it'd be not just gravy, but supergravy.

Generally speaking, routers are for the most part just small computers running a minimal (in most cases) OS, that conduct negotiations between your computer and the rest of the internet world. They usually do not require any type of driver or software installation to do their jobs and as such are not likely to be the actual cause of your computer issues, but rather just the device that allows the actual culprit to busy up your computer.
Have you tried booting into safemode with networking by tapping the F8 key at startup / boot time, just to see if your problem persists. Safemode with networking, will generally support networking activity while inhibiting the startup of unnecessary software and services, that I suspect might actually be your problem. Since there is a lot of software out there that can cause these types of issues, have you done a thorough and comprehensive scan for Virus and or Malware problems? Unfortunately safemode with networking will not in some instances keep these programs from executing, you may need to try some scans with some antimalware products, if you need some help with that post back and we'll provide some suggestions and links.

So, I tried updating drivers. I tried disabling programs. I tried scanning for viruses. I tried scanning for spyware. I tried removing hardware. I tried avoiding certain applications. I tried always running other applications.

What a surprise, I actually, yes, did what I said I did.

It's entirely possible the issue is with the card that permits wifi connection to the router, except that there's also a monumental ****up when I connect via cable to the router, which bypasses that little thinger.

Sure, could be some software, but as said: I've scanned for all spyware, I've scanned for all malware, I am completely at a damn loss as to what it could be. None of my other utilities have given me ANY crap before.

Did your ISP require the installation of any software to support your connection to them?
Can I assume that you have tried safemode with networking?
Have you tried disabling IPv6 in the properties of your network adapter? Some routers do have issues with IPv6.
Since according to what you've mentioned so far, the problem persists with both wired and wireless, so if we could, for the purpose of troubleshooting, let's focus on the wired connection and disable the wireless connection in device manager.
When you described, how you reconnected the router and "BAM, down it went" are you able to do anything at that time, can you open task manager and see what process(s) are consuming the system resources or is it pretty much locked up?

The moment it starts going down I can start no new processes and generally cannot do anything with what is already running except maybe flip between a few windows. Task manager is definitely out.

And what steps do you then take to recover. If you simply, disconnect the network, is everything alright again, or does it require a hard shut down to recover?
Did your ISP require the installation of any software to support your connection to them?
Can I assume that you have tried safemode with networking?
Have you tried disabling IPv6 in the properties of your network adapter? Some routers do have issues with IPv6.