I don't know if niladri ever solved his problem, but I've just experienced the same thing and thought I would share my solution.
I had to remove a hard drive from my system recently for some troubleshooting and after I returned it to the case, I was experiencing close to 100% CPU usage almost all the time. With Process Explorer and Microsoft's RATTV3 tool, I was able to isolate the problem to hardware interrupts and DPCs being generated by my D-Link DWL-G510 wireless adapter. When I disabled the card, the high CPU usage disappeared entirely. When I re-enabled it, back came the high usage.
I tried everything. Taking the card out and cleaning the contacts. Blowing out dust from the slot. Replacing the driver in case it had become corrupted (I already was using the most recent version). Even installing a previous version of the driver. All to no avail!
I had come to the conclusion that something must have gone bad on the card and I would simply have to replace it. In fact, if it hadn't been late Saturday night, after every store was already closed, I would have immediately gone out and bought a replacement card. Instead, since I couldn't do that, I decided to do one last search of the Internet to find a possible soultion (I'd already tried more times than I could count). And that's when I ran across a post on ask-leo.com, buried on the fourth page of a thread titled "My new network card lights up, but Windows doesn't find it. Why?" (
http://ask-leo.com/comments_001980.php?page=4).
In a post from five years ago, a user named Kenny reported:
"If you have high CPU usage with the D-Link DWL-G510, try this simple test:
"Open [Windows Task Manager] and monitor CPU usage. If it is running high, normally you could check the Processes to see which ones were using the CPU. But if the System Idle Process is running near 99%, that means no other processes are using it. This scenario indicates that you may only have an antenna problem.
"I had high CPU usage of around 20% whenever I connected using my D-Link DWL-G510 wireless adapter. I tried many other fixes with no luck. In my case, I had wires from the mouse, keyboard and monitor draped around the wireless antenna. When I moved the wires away, my CPU usage dropped to 1-2%. However, when I moved the antenna down toward the wooden desk, the CPU went back up to 20%. So, it seems that any antenna interference is bad. But it's an easy fix!"
So I repositioned my adapter's antenna ... AND IT WORKED!
In my case, I didn't have wires drapped around the antenna, but before the hard drive removal, I'd had the antenna positioned parallel to the ground. When putting the drive back in, the antenna accidentally had been repositioned to be nearly vertical. As soon as I turned it back to parallel, the hardware interrupts and DPC's dropped to practically zero!
So, before anyone experiencing this problem decides to jettison their D-Link adapter, try repositioning the antenna. I know it sounds unbelievable, but it's true! Apparently, the antenna is incredibly sensitive.