I write this post in true desperation with the hope that someone my be able to help end the turmoil which I am faced with ( and im not referring to the fact Ted has been kicking my butt lately    )

Since the latest patch i have been experincing ever increasing diconnects from BO, in the form of 'server no longer available' or 'error black ops server is not available at this time try again later. Please visit www.callofduty.com/blackops/status/update'

It has now gotten to the point where i can barely complete a single map rotation I have scrolled through loads of forums but have yet to find the solution, so im wondering if anyone here had the same issue & resolved it.

I have tried the following:
full uninstall/reinstall of BO
full uninstall/reinstall steam
disable steamguard
disabled cloud
disabled firewall
restored config_mp file to default
deleted clientrigistry.blob file
rebooted router & PC
verified steam files
ran disk clean etc

I have changed hardware but it was done after i started experiencing issues, my current setup is
vista ultimate 64
asus striker II extreme board
QX6950 cpu
8 GB ram
GTX 260 896MB

Any help or advice on what else to try would be extremely appreciated  

have you tried starting blackops and tabing out to your task manager and setting Blackops priority on high,and steam on low?
or in your steam settings changed the area you get ur dl info from?
sounds like a packet flow interruption,or lsing conection with steam....im pretty sure the same thing has happened to me,but so rarely ive never done anything about it

Yeah, its not an issue with the servers, your game or your setup (however I would suggest switching to Windows 7). Its a steam connection loss issue.

One other thing besides what H1N1 already mentioned is to set the DMZ for your router so your PC's IP is not blocked at all by the router. You may have something blocking a port on the router side and you aren't aware of it.

Are the ports for steam/bo open per the sticky in this forum? If the ports arent open (there are only two) in your router then that may cause the interruption.

I probably haven't experienced as many 'server connection' issues as yourself, but I have had several. In the last week I've noticed 3-4 steam updates where I get the server unavailable messages. These are resolved after 10-20 minutes - doesn't affect TS though.
I'm also seeing more instances of my broadband dropping almost daily - but that might be due to the number of devices my family have connected.

may i also point out that windows vista 64 if used on a wireless connection has a feature called network discovery which every so oftern scans the network for new hardware, i discovered this with waw when i got massive lag spikes and after about 1hour or even less i would get disconnected there is a way of turning this off if you want more info let me know

That's interesting Mr-T. I have a small hub attached to my router for my local lan but also more than 10 wireless devices. I have noticed in the last week that my gaming machine detects the xbox media center.
Time to turn-off the detection.

thanks for the input guys, forgot to mension that I have the port forwarded & I not connected by wifi)

touch wood though, changing the dl server in steam has proved successful so far with 2hrs of soild gameplay  

keeping the figures crossed it will be the permament solution.

Thanks again for your assistance  

I suffered through the exact same problem until the last patch. Since the patch not one 'server no longer available' or 'error black ops server is not available at this time try again later. Please visit www.callofduty.com/blackops/status/update'  I have no clue where the problem lies Is it BO-Steam or what. But I tried everything mentioned here to no avail. Best guess in lies in Blackops. If you notice alot of the patches mentioned Improved network performance. The only connectivity problem I have now is at any time while black ops is running my entire network will crash. Meaning none of the five pc on the network can browes the internet. Go figure. Just have to wait it out. I run Vista 32