Cookies are
text string messages given to a Web browser by a Web server. Whenever you visit a web page or navigate different pages with your browser, the web site generates a unique ID number which your browser stores in a text (cookie) file that is sent back to the server each time the browser requests a page from that server. Cookies allow third-party providers such as ad serving networks, spyware or adware providers to track personal information. The main purpose of cookies is to identify users and prepare customized Web pages for them.
The type of cookie that is a cause for some concern are "
tracking cookies" because they can be considered a privacy risk. These types of cookies are used to track your Web browsing habits (your movement from site to site). Ad companies use them to record your activity on all sites where they have placed ads. They can keep count of how many times you visited a web page, store your username and password so you don't have to log in and retain your custom settings. When you visit one of these sites, a cookie is placed on your computer. Each time you visit another site that hosts one of their ads, that same cookie is read, and soon they have assembled a list of which of their sites you have visited and which of their ads that you have clicked on. They are used all over the Internet and advertisement companies often plant them whenever your browser loads one of their banners.
Cookies are NOT a "threat". As text files they cannot be executed to cause any damage.
Cookies do not cause any pop ups nor do they install malware. As long as you surf the Internet, you are going to get cookies and some of your security programs will flag them for removal. However, you can minimize this by reading "
Blocking & Managing Unwanted Cookies" and "
Block Third-Party Cookies in IE7".
Try the suggestions mentioned in
Slow Computer/Browser? Check here first; it may not be malware.
There are reasons for slowness besides malware - i.e. disk fragmentation, disk errors, corrupt system files, too many startup programs, unnecessary services running, not enough RAM, dirty hardware components, etc. As your system gets older it becomes filled with more files/programs and has a natural tendency to slow down so cleaning and regular maintenance is essential.Note: If you are not on a local area network (LAN), disable the Workstation Service which creates and maintains client network connections to remote servers and that should also help to speed up your boot time.