The health of your computer can affect your Internet connection. Spyware and viruses can definitely cause problems, but your Internet connection speed can also be affected by add-on programs, the amount of memory the computer has, hard disk space and condition, and the programs that are running.
Two of the most frequent causes of poor Internet performance are spyware and viruses. Spyware can slow your system by interfering with your browser and monopolizing your Internet connection. Spyware monitors your Internet use and keystrokes, which adds delays. The problem is compounded when there are multiple spyware programs running at the same time. If the problem is severe enough, you can lose connectivity altogether. To get your Internet performance back, you should regularly run an antispyware program to clean out any spyware infestation. For more information, see Scan for spyware and other potentially unwanted software.
Computer viruses can also cause poor Internet performance. When a virus infects a computer, it installs computer code which will attempt to propagate itself, usually by sending copies of itself through e‑mail. Some viruses can multiply at the rate of hundreds of e‑mail messages per minute, which leaves little computing power and Internet connection bandwidth for anything else. Viruses often don't give any obvious indication that they are running, so it's best to run your antivirus software at all times. For more information about dealing with viruses, see Viruses: frequently asked questions.
Browser add-ons also cause performance problems. Browser add-ons are programs, such as multimedia add-ons, search bars, or other programs that usually appear on your browser's toolbar. Many browser add-ons can add to a rich browsing experience, offering multimedia or specialized document viewing. However, some add-ons can slow your Internet connection. If you suspect that add-ons are causing slow performance, try starting Internet Explorer in Add-ons disabled mode. Add-ons are disabled only for the session, but if you find your performance improves, you can use the Add-on Manager to turn them off permanently. To access the Add-on Manager from Internet Explorer, click the Tools button, and then click Manage Add-ons. For more information, see How do browser add-ons affect my computer?
Like all computer programs, Internet Explorer requires a certain amount of computing power, memory, and disk space to run efficiently. Every webpage you view is first downloaded to memory and then saved to temporary disk files. Running another program that is using lots of memory and computing power can compete with Internet Explorer and cause delays. If you find your Internet connection running slowly and you have other programs running, try closing them. If you want to run several programs, consider increasing the memory you have on your computer. Low disk space can also cause performance problems. You can increase your disk space by deleting Internet Explorer's temporary files. To learn how to delete temporary files, see Delete webpage history.
Occasionally, settings get changed in Internet Explorer that could possibly affect how Internet Explorer works. You can reset Internet Explorer to its default settings. For more information, see Reset Internet Explorer settings. Resetting Internet Explorer isn't reversible, so you should read the list of settings that are affected before resetting.