I have a problem with my new USB disk. When I connect it to my laptop with Windows XP SP2 it takes about 4-5min until Windows recognizes it and shows it as a new disk. I can also see (disk's LED is blinking) that something is scanning the disk when I connect it; when this is done Windows immediately recognize it.

Also when I'm copying data to this disk the speed is about 3.5MB/sec. It's connected using USB2.0.

I tried to check for spyware (using Spybot), also tried running Windows in safe mode. But still have the same problems.

Do you have any idea what could help to solve this problem?

On Windows Vista (another laptop) everything is ok, disk loads in about 15sec and speed is about 20-30MB/sec.

Edit: I tried to update to SP3 - no change

Edit2: When this "strange" scanning occurs I can see that DPCs process is taking about 50% of CPU. When the scan ends (after 5min) this process take 0% again.

Edit3: About the scan time, currently it's taking about 5min, but this time is growing as I'm adding more data to the disk, currently its about 40GB and I don't want to see how long it will take with 1000GB.

Thanks a lot for every advice!