|You can check battery condition if you have MS mouse driver version 7.10 installed. |
If you have older mouse software or none (Windows installs one during installation. This I call none), you should install the latest v. 7.10 x86 or x64 depending on your Windows installation.
Then check battery. If batteries need replacement, replace them and test your desktop responsiveness. If still bad, you can borrow a mouse and try with that one before you spend money and buy a new one.
My problem was, when I wanted to click, for example, "X" button to close a window or "back" button to go back to a previous page in IE8 or when I wanted to place the cursor on a specific place in a .txt document to make a correction, it took ages to do so. I clicked many times to place the cursor in a text file.